RESUMEN

OBJECTIVE: Refractory status epilepticus is one of the most life-threatening neurological emergencies and is characterized by high morbidity and mortality. Additionally, the use of anti-inflammatory drugs during this period is very controversial. Thus, this study has been designed to analyze the effect of a low dose of indomethacin (a COX inhibitor) on the expression of inflammatory molecules. METHOD: The hippocampus of rats submitted to pilocarpine-induced long-lasting status epilepticus was analyzed to determine the expression of inflammatory molecules with RT-PCR and immunohistochemistry. RESULTS: Compared with controls, reduced levels of the kinin B2 receptors IL1ß and TNFα were found in the hippocampus of rats submitted to long-lasting status epilepticus and treated with indomethacin. CONCLUSIONS: These data show that low doses of indomethacin could be employed to minimize inflammation during long-lasting status epilepticus.

Asunto(s)

Inhibidores de la Ciclooxigenasa/farmacología , Hipocampo/efectos de los fármacos , Indometacina/farmacología , Monocinas/efectos de los fármacos , Receptores de Bradiquinina/efectos de los fármacos , Estado Epiléptico/tratamiento farmacológico , Animales , Modelos Animales de Enfermedad , Regulación hacia Abajo/efectos de los fármacos , Interleucina-1beta/análisis , Interleucina-1beta/efectos de los fármacos , Masculino , Monocinas/análisis , Pilocarpina , Ratas Wistar , Receptor de Bradiquinina B1/análisis , Receptor de Bradiquinina B1/efectos de los fármacos , Receptor de Bradiquinina B2/análisis , Receptor de Bradiquinina B2/efectos de los fármacos , Receptores de Bradiquinina/análisis , Estado Epiléptico/inducido químicamente , Factor de Necrosis Tumoral alfa/análisis , Factor de Necrosis Tumoral alfa/efectos de los fármacos

RESUMEN

OBJECTIVE: Refractory status epilepticus is one of the most life-threatening neurological emergencies and is characterized by high morbidity and mortality. Additionally, the use of anti-inflammatory drugs during this period is very controversial. Thus, this study has been designed to analyze the effect of a low dose of indomethacin (a COX inhibitor) on the expression of inflammatory molecules. METHOD: The hippocampus of rats submitted to pilocarpine-induced long-lasting status epilepticus was analyzed to determine the expression of inflammatory molecules with RT-PCR and immunohistochemistry. RESULTS: Compared with controls, reduced levels of the kinin B2 receptors IL1β and TNFα were found in the hippocampus of rats submitted to long-lasting status epilepticus and treated with indomethacin. CONCLUSIONS: These data show that low doses of indomethacin could be employed to minimize inflammation during long-lasting status epilepticus. .

Asunto(s)

Animales , Masculino , Inhibidores de la Ciclooxigenasa/farmacología , Hipocampo/efectos de los fármacos , Indometacina/farmacología , Monocinas/efectos de los fármacos , Receptores de Bradiquinina/efectos de los fármacos , Estado Epiléptico/tratamiento farmacológico , Modelos Animales de Enfermedad , Regulación hacia Abajo/efectos de los fármacos , Interleucina-1beta/análisis , Interleucina-1beta/efectos de los fármacos , Monocinas/análisis , Pilocarpina , Ratas Wistar , Receptor de Bradiquinina B1/análisis , Receptor de Bradiquinina B1/efectos de los fármacos , /análisis , /efectos de los fármacos , Receptores de Bradiquinina/análisis , Estado Epiléptico/inducido químicamente , Factor de Necrosis Tumoral alfa/análisis , Factor de Necrosis Tumoral alfa/efectos de los fármacos

RESUMEN

Focal and segmental glomerulosclerosis (FSGS) is one of the most important renal diseases related to end-stage renal failure. Bradykinin has been implicated in the pathogenesis of renal inflammation, whereas the role of its receptor 2 (B2RBK; also known as BDKRB2) in FSGS has not been studied. FSGS was induced in wild-type and B2RBK-knockout mice by a single intravenous injection of Adriamycin (ADM). In order to further modulate the kinin receptors, the animals were also treated with the B2RBK antagonist HOE-140 and the B1RBK antagonist DALBK. Here, we show that the blockage of B2RBK with HOE-140 protects mice from the development of FSGS, including podocyte foot process effacement and the re-establishment of slit-diaphragm-related proteins. However, B2RBK-knockout mice were not protected from FSGS. These opposite results were due to B1RBK expression. B1RBK was upregulated after the injection of ADM and this upregulation was exacerbated in B2RBK-knockout animals. Furthermore, treatment with HOE-140 downregulated the B1RBK receptor. The blockage of B1RBK in B2RBK-knockout animals promoted FSGS regression, with a less-inflammatory phenotype. These results indicate a deleterious role of both kinin receptors in an FSGS model and suggest a possible cross-talk between them in the progression of disease.

Asunto(s)

Glomeruloesclerosis Focal y Segmentaria/patología , Receptores de Bradiquinina/fisiología , Animales , Bradiquinina/análogos & derivados , Bradiquinina/farmacología , Glomeruloesclerosis Focal y Segmentaria/metabolismo , Ratones , Ratones Noqueados , Receptores de Bradiquinina/efectos de los fármacos , Receptores de Bradiquinina/genética

RESUMEN

Bradykinin B1 receptors are not expressed under physiological conditions but are induced under inflammatory conditions. In isolated human umbilical vein, a spontaneous bradykinin B1 receptor sensitization process has been demonstrated. On the other hand, retinoids have been shown to exert anti-inflammatory and immunomodulatory actions. We have now examined the effects of all-trans-retinoic acid and 9-cis-retinoic acid on the bradykinin B1 receptor-sensitized responses in human umbilical vein. Both retinoids produced a concentration-dependent rightward shift of the concentration-response curves for the bradykinin B1 receptor agonist, des-Arg(9)-bradykinin. Retinoid treatment did not modify the responses to bradykinin B1 receptor-unrelated agonists, bradykinin or serotonin. In conclusion, retinoids inhibit bradykinin B1 receptor-sensitized responses and this action could participate in their anti-inflammatory and immunomodulatory effects.

Asunto(s)

Antineoplásicos/farmacología , Receptores de Bradiquinina/efectos de los fármacos , Retinoides/farmacología , Tretinoina/farmacología , Venas Umbilicales/efectos de los fármacos , Alitretinoína , Bradiquinina/farmacología , Relación Dosis-Respuesta a Droga , Humanos , Receptor de Bradiquinina B1 , Receptores de Bradiquinina/fisiología , Venas Umbilicales/fisiología

RESUMEN

1. Intradermal (i.d.) injection of cytokines, IL-1beta and TNFalpha (5 ng, 60 and 30 min prior) produces a rapid onset up-regulation of des-Arg9-BK-mediated rat paw oedema. Here we analyse the mechanisms involved in des-Arg9-BK-induced oedema in animals pre-treated with IL-1beta or TNFalpha. 2. Co-injection of anti-IL-1beta, anti-TNFalpha and anti-IL-8 (50 ng) significantly inhibited des-Arg9-BK-induced oedema in animals pre-treated with IL-1beta (65, 37 and 42%) or TNFalpha (39, 64, 25%). IL-1 receptor antagonist (IRA, 100 microg) or IL-10 (10 ng) inhibited the oedema caused by des-Arg9-BK, in rats that had received either IL-1beta (67 and 63%) or TNFalpha (46 and 35%). 3. Co-injection of the PKC inhibitors, staurosporine (10 nmol) or RO 318220 (30 nmol) inhibited des-Arg9-BK-induced paw oedema (44 and 42% for IL-1beta and, 53 and 30% for TNFalpha, respectively). Genistein (tyrosine kinase inhibitor, 2.5 mg kg-1, s.c.) or PD 098059 (MAP-kinase inhibitor, 30 nmol) produced marked inhibition of des-Arg9-BK-induced oedema (58 and 39% for IL-1beta and 31 and 35% for TNFalpha respectively). 4. The NF-kappaB inhibitors TLCK (2 mg kg-1, i.p.) and PDCT (100 mg kg-1, i.p.) significantly inhibited the oedema of des-Arg9-BK in IL-1beta (27 and 83%) or TNFalpha (28 and 80%) pre-treated animals. 5. It is concluded that up-regulation of B1 receptors modulated by IL-1beta or TNFalpha involves the release of other cytokines, activation of PKC and tyrosine kinase pathways, co-ordinated with the activation of MAP-kinase and nuclear factor kappaB, reinforcing the view that B1 receptors may exert a pivotal role in modulating chronic inflammatory processes.

Asunto(s)

Interleucina-1/metabolismo , FN-kappa B/metabolismo , Proteínas Quinasas/metabolismo , Receptores de Bradiquinina/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Animales , Bradiquinina/análogos & derivados , Edema/inducido químicamente , Mediadores de Inflamación , Interleucina-1/farmacología , Masculino , FN-kappa B/efectos de los fármacos , Proteínas Quinasas/efectos de los fármacos , Ratas , Receptor de Bradiquinina B1 , Receptores de Bradiquinina/efectos de los fármacos , Factor de Necrosis Tumoral alfa/farmacología , Regulación hacia Arriba

RESUMEN

This paper studies the modulation by bradykinin of the ouabain-insensitive Na+-ATPase activity in both renal cortex homogenate and basolateral membrane from proximal tubule. The increase in bradykinin concentration from 10-14 to 10-10 M stimulated the ouabain-insensitive Na+-ATPase activity in cortex homogenates about 2.2-fold, but inhibited the enzyme activity of basolateral membrane preparations by 60%. In both preparations, the maximal effect was obtained with 10-10 M bradykinin. Further increase in the concentration of bradykinin completely abolished these effects. The antagonist of the B2 receptor, Hyp3, completely abolished the effect of 10-10 M bradykinin on the Na+-ATPase activity in the basolateral membrane preparation in a dose-dependent manner, but had no effect on the bradykinin stimulated enzyme activity of the cortex homogenate. Furthermore, in the presence of 10-7 M Hyp3, 10-10 M bradykinin stimulated the Na+-ATPase activity by 45% in the basolateral membrane preparations. The increase in des-Arg9-bradykinin concentration from 10-12 to 10-7 M, an agonist of the B1 receptor, stimulated the Na+-ATPase activity of the cortex homogenates and of the basolateral membrane preparations by 105 and 148%, respectively. In the presence of 25 microM mergetpa, an inhibitor of kininase I, the increase in bradykinin concentration from 10-12 to 10-10 M promoted similar inhibition of the Na+-ATPase activity of both cortex homogenates and basolateral membrane preparations. These results suggest that bradykinin stimulated the Na+-ATPase activity of proximal tubule through the interaction with B1 receptors and inhibited the enzyme through the interaction with B2 receptors. Furthermore, the cortex homogenate expresses a kininase I activity that cleaves bradykinin to des-Arg9-bradykinin.

Asunto(s)

Adenosina Trifosfatasas/metabolismo , Bradiquinina/farmacología , Proteínas de Transporte de Catión , Túbulos Renales Proximales/efectos de los fármacos , Animales , Membrana Celular/efectos de los fármacos , Membrana Celular/enzimología , Activación Enzimática/efectos de los fármacos , Corteza Renal/efectos de los fármacos , Corteza Renal/enzimología , Túbulos Renales Proximales/enzimología , Lisina Carboxipeptidasa , Ouabaína , Peptidil-Dipeptidasa A , Receptor de Bradiquinina B1 , Receptor de Bradiquinina B2 , Receptores de Bradiquinina/efectos de los fármacos , Receptores de Bradiquinina/metabolismo , Porcinos

RESUMEN

Bradykinin B1 receptor-mediated responses increase as a function of in vitro incubation in the human umbilical vein. When tissues were continuously treated with the protein synthesis inhibitor, cycloheximide, or with the protein trafficking inhibitor, brefeldin A, pEC50 and maximal response to the selective bradykinin B1 receptor agonist, des-Arg9-bradykinin, were significantly diminished. The anti-inflammatory steroid, dexamethasone, produced a rightward shift of the concentration-response curve to des-Arg9-bradykinin, without affecting the maximal response. Furthermore, lipopolysaccharide or recombinant human interleukin-1 beta potentiate the bradykinin B1-sensitized responses, showing a leftward shift of the concentration-response curve to des-Arg9-bradykinin, without modifying the maximal response. On the other hand, bradykinin B2 receptor-mediated responses were unaffected by continuous exposure to cycloheximide, dexamethasone or lipopolysaccharide. These results provide pharmacological evidence to support the view that the de novo synthesis of bradykinin B1 receptors is involved in the induction of vascular responses in the human umbilical vein. This up-regulation process seems to be selective for bradykinin B1 receptors. The inhibitory effect of dexamethasone and the potentiating actions of lipopolysaccharide and exogenous human recombinant interleukin-1 beta on des-Arg9-bradykinin-mediated responses, suggest the possible role of interleukin-1 beta in the bradykinin B1 receptor up-regulation phenomenon in human umbilical vein.

Asunto(s)

Receptores de Bradiquinina/metabolismo , Venas Umbilicales/metabolismo , Antiinflamatorios/farmacología , Bradiquinina/análogos & derivados , Bradiquinina/farmacología , Antagonistas de los Receptores de Bradiquinina , Brefeldino A/farmacología , Cicloheximida/farmacología , Dexametasona/farmacología , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Técnicas In Vitro , Interleucina-1/farmacología , Contracción Isométrica/efectos de los fármacos , Polisacáridos Bacterianos/farmacología , Embarazo , Inhibidores de la Síntesis de la Proteína/farmacología , Receptor de Bradiquinina B1 , Receptores de Bradiquinina/efectos de los fármacos , Proteínas Recombinantes/farmacología , Venas Umbilicales/efectos de los fármacos , Regulación hacia Arriba

RESUMEN

OBJECTIVE: To characterize the kinin receptor subtype involved in the relaxation of human isolated corpus cavernosum (HCC) induced by bradykinin (BK), Lys-bradykinin (Lys-BK), Met-Lys-bradykinin (Met-Lys-BK) and des-Arg9-bradykinin, and to investigate whether the kinin-induced relaxation of HCC results from the stimulation of nonadrenergic, noncholinergic (NANC) neurons supplying the cavernosal tissue. MATERIALS AND METHODS: Excised HCC tissues were immediately placed in Krebs solution and kept at 4 degrees C until use (never > 24 h after removal). HCC was cut in strips of approximately 2 cm, suspended in a cascade system and superfused with oxygenated and warmed Krebs solution at 5 mL/min. After equilibration for approximately 90 min, noradrenaline (3 micromol/L) was infused to induce a submaximal contraction of the HCC strips. The release of cyclo-oxygenase products was prevented by infusing indomethacin (6 micromol/L). HCC strips were calibrated by injecting a single bolus of the nitrovasodilator glyceryl trinitrate (GTN) and the sensitivity of the tissues adjusted electronically to be similar. The agonists (kinins, histamine and acetylcholine) were injected as a single bolus (up to 100 microL) and the relaxation of HCC expressed as a percentage of the submaximal relaxation induced by GTN. RESULTS: Bradykinin, Lys-BK and Met-Lys-BK significantly relaxed the HCC tissues; on a molar basis, there was no statistical difference among the degrees of relaxation induced by these peptides. The B1 kinin receptor agonist des-Arg9-bradykinin had no effect on the HCC. The infusion of the B2 kinin receptor antagonist Hoe 140 (50 nmol/L) virtually abolished the relaxation induced by BK, Lys-BK and Met-Lys-BK without affecting those induced by acetylcholine and histamine. The infusion of the nitric oxide synthase inhibitor N(omega)-nitro-L-arginine methyl ester increased the tone of the HCC tissues and significantly reduced (P < 0.01) the relaxation induced by BK (74%), Lys-BK (90%), Met-Lys-BK (87%) and acetylcholine (89%) without affecting those induced by GTN. The subsequent infusion of L-arginine (300 micromol/L) partially reversed the increased tone and significantly (P < 0.01) restored the relaxation induced by BK, Lys-BK and Met-Lys-BK. The results were similar with the novel guanylate cyclase inhibitor 1H-[1,2,4] oxadiazolo[4,3,-alquinoxalin-1-one] which reduced by > 95% (P < 0.01) the relaxation induced by BK, Lys-BK, Met-Lys-BK, acetylcholine and GTN. The infusion of the sodium-channel blocker tetrodotoxin had no significant effect on the BK-, GTN- and acetylcholine-induced relaxation of HCC. CONCLUSION: This study clearly showed the existence of functional B2 kinin receptors in human erectile tissues that when activated lead to the release of NO and hence relaxation of the HCC tissues. As tetrodotoxin failed to affect the kinin-induced relaxation of HCC strips, it is likely that these peptides release NO from the endothelium of sinusoidal capillaries rather than from neuronal sources supplying the cavernosal tissue. Although tissue kallikreins and their components have been found in the male reproductive system, the physiopathological importance of these findings has yet to be elucidated.

Asunto(s)

Bradiquinina/análogos & derivados , Bradiquinina/farmacología , Calidina/farmacología , Pene/efectos de los fármacos , Receptores de Bradiquinina/química , Adolescente , Antagonistas Adrenérgicos beta/farmacología , Adulto , Antagonistas de los Receptores de Bradiquinina , Inhibidores Enzimáticos/farmacología , Humanos , Masculino , Persona de Mediana Edad , NG-Nitroarginina Metil Éster/farmacología , Óxido Nítrico/farmacología , Erección Peniana/efectos de los fármacos , Pene/fisiología , Receptores de Bradiquinina/efectos de los fármacos

RESUMEN

The action of bradykinin was studied in rat-1 fibroblasts stably expressing alpha1b-adrenoceptors. It was observed that bradykinin and kallidin markedly increase cytosol calcium concentration, but that the B1 agonist, des-Arg9-bradykinin, only mimicked this effect to a minimal extent. Antagonists, selective for the B2 subtype, such as Hoe 140, blocked this effect of bradykinin and kallidin. Similarly, bradykinin and kallidin stimulated the production of inositol phosphates and B2 antagonists blocked their actions. The possibility that bradykinin could modulate alpha1b-adrenoceptors was studied. It was observed that bradykinin and kallidin increased alpha1b-adrenoceptor phosphorylation and that such effect was also blocked by Hoe 140. Interestingly, the ability of norepinephrine to increase intracellular calcium concentration was not altered by pretreatment of the cells with bradykinin, i.e. bradykinin induced alpha1b-adrenoceptor phosphorylation but this did not lead to receptor desensitization.

Asunto(s)

Receptores Adrenérgicos alfa 1/fisiología , Receptores de Bradiquinina/fisiología , Transducción de Señal , Animales , Bradiquinina/análogos & derivados , Bradiquinina/farmacología , Calcio/metabolismo , Línea Celular , Cricetinae , Citosol/metabolismo , Endotelinas/farmacología , Fosfatos de Inositol/metabolismo , Calidina/farmacología , Norepinefrina/farmacología , Fosforilación , Ratas , Receptor de Bradiquinina B2 , Receptores Adrenérgicos alfa 1/efectos de los fármacos , Receptores de Bradiquinina/efectos de los fármacos , Proteínas Recombinantes/efectos de los fármacos , Proteínas Recombinantes/metabolismo , Transfección

RESUMEN

1. The effect of central injection of selective kinin B1 and B2 receptor antagonists on the febrile response induced by endotoxin (E. coli lipopolysaccharide, LPS) in rats was investigated. 2. Intracerebroventricular (i.c.v.) injection of a selective B2 receptor antagonist (Hoe-140, 8 nmol) reduced the early (0-2 h), but increased the late phase (4-6 h) of the febrile response induced by intravenous (i.v.) injection of LPS (0.5 microgram kg-1). 3. Co-administration of Hoe-140 (8 nmol, i.c.v.) with LPS (0.5 microgram kg-1, i.v.), followed 2.5 h later by the i.c.v. injection of a selective B1 receptor antagonist [des-Arg9-Leu8]-bradykinin (BK, 8 nmol), significantly reduced the febrile response induced by LPS throughout the whole experimental period. 4. Intravenous injection of Hoe-140 (1 mg kg-1) significantly reduced the febrile response induced by LPS (0.5 microgram kg-1, i.p.). 5. Pretreatment (24 h) with LPS (0.5 microgram kg-1, i.v.) reduced the febrile response induced by BK or [Tyr8]-BK (both, 5 nmol, i.c.v.), but markedly increased the febrile response induced by [des-Arg9]-BK (5 nmol, i.c.v.). The response induced by [des-Arg9]-BK in LPS-pretreated rats was significantly inhibited by co-injection of [des-Arg9-Leu8]-BK (15 nmol, i.c.v.). 6. The results suggest that kinins are involved in the induction of LPS-induced fever and that central B2 and B1 receptors are activated during the initial and late phase of this response, respectively. The results also suggest that downregulation and/or desensitization of B2 receptors and induction and/or upregulation of B1 receptors in LPS-pretreated animals may have a significant pathophysiological role in the induction and maintenance of fever. These observations may be specifically important in the case of chronic inflammatory conditions, because the BK metabolite [des-Arg9]-BK, so far considered an inactive metabolite, acquires an active and relevant role with the progressive expression of B1 receptors that occurs in such states.

Asunto(s)

Bradiquinina/análogos & derivados , Sistema Nervioso Central/efectos de los fármacos , Endotoxinas/farmacología , Fiebre/fisiopatología , Lipopolisacáridos/efectos adversos , Receptores de Bradiquinina/efectos de los fármacos , Animales , Bradiquinina/efectos adversos , Masculino , Ratas , Ratas Wistar

RESUMEN

This study describes the contractile action of bradykinin on rat isolated mesenteric arterial rings and a possible mechanism responsible for this action. Bradykinin induced dose-dependent contraction of relaxed mesenteric arterial rings from Holtzman rats, but not from Wistar rats. A second bradykinin challenge in the same ring induced a very small effect or no effect at all. Destruction of the endothelium did not modify the response to bradykinin. des-Arg9-[Leu8]bradykinin failed to antagonize bradykinin's action. HOE 140 (D-Arg- [Hyp3, Thi5,D-Tic7,Oic8]bradykinin) reduced bradykinin-induced contractions. Indomethacin abolished the contractile response to bradykinin; prostaglandin F2 alpha induced a long-lasting contraction, dissimilar from that induced by bradykinin; L-655,240 (3-[1-(4-chlorobenzyl)-5-fluoro-3-methyl-indol-2-yl]-2,2-dimethyl propanoic acid), an antagonist of the thromboxane receptor, inhibited bradykinin-induced contractions. These results suggest that bradykinin-induced contraction in mesenteric arterial rings is indirect, through activation of bradykinin B2 receptors, resulting in liberation of prostanoids from outside the endothelium. Thromboxane A2 is probably an intermediate in this response but we cannot exclude the participation of other prostanoids.

Asunto(s)

Ácido Araquidónico/metabolismo , Bradiquinina/farmacología , Contracción Muscular/efectos de los fármacos , Músculo Liso Vascular/efectos de los fármacos , Animales , Bradiquinina/metabolismo , Antagonistas de los Receptores de Bradiquinina , Dinoprost/farmacología , Endotelio Vascular/efectos de los fármacos , Endotelio Vascular/fisiología , Inhibidores Enzimáticos/farmacología , Imidazoles/farmacología , Técnicas In Vitro , Indoles/farmacología , Indometacina/farmacología , Arteria Mesentérica Superior/efectos de los fármacos , Arteria Mesentérica Superior/fisiología , Relajación Muscular/efectos de los fármacos , Músculo Liso Vascular/fisiología , Antagonistas de Prostaglandina/farmacología , Ratas , Ratas Sprague-Dawley , Ratas Wistar , Receptores de Bradiquinina/efectos de los fármacos , Receptores de Bradiquinina/fisiología

RESUMEN

The present study was undertaken to demonstrate the presence of bradykinin B1 receptors mediating contraction of human umbilical vein. The bradykinin B1 receptor selective agonist, des-Arg9-bradykinin, produced a dose-dependent contractile response of human umbilical vein rings. Furthermore, des-Arga-bradykinin-mediated response increased in a time-dependent manner in vitro. The maximal response to des-Arg9-bradykinin, expressed as percentage of the maximum elicited by serotonin, was: 10 +/- 2 at 15 min, 55 +/- 5 at 120 min and 80 +/- 3 at 300 min. Des-Arg9-bradykinin-mediated contractions were inhibited by the specific bradykinin B1 receptor antagonist des-Arg9-[Leu8]bradykinin which produced parallel shifts in the dose-response curve to the selective bradykinin B1 receptor agonist. Schild regression analysis of data established a pA2 value of 6.16 +/- 0.06. Kinin-induced contraction was not modified by pre-treatment with indomethacin (10 microM), a cyclo-oxygenase inhibitor. On the other hand, continuous exposure to the anti-inflammatory steroid dexamethasone (100 microM) or to the protein synthesis inhibitor cycloheximide (70 microM) largely prevented the sensitization to des-Arg9-bradykinin in incubated human umbilical vein rings. These results confirm the presence of bradykinin B1 receptors which mediate contraction in isolated human umbilical vein. These responses are up-regulated in a time- and protein synthesis-dependent process.

Asunto(s)

Receptores de Bradiquinina/efectos de los fármacos , Venas Umbilicales/efectos de los fármacos , Antiinflamatorios/farmacología , Bradiquinina/análogos & derivados , Bradiquinina/farmacología , Antagonistas de los Receptores de Bradiquinina , Inhibidores de la Ciclooxigenasa/farmacología , Dexametasona/farmacología , Femenino , Humanos , Técnicas In Vitro , Contracción Muscular/fisiología , Embarazo , Receptor de Bradiquinina B1 , Receptores de Bradiquinina/agonistas , Regulación hacia Arriba/efectos de los fármacos

RESUMEN

1. The effect of intracerebroventricular (i.c.v.) injection of bradykinin (BK) and related peptides was tested on the dental pulp electrical stimulation threshold (DPEST) in rats. 2. BK (4, 8 and 16 nmol) induced a dose-dependent increase of DPEST, indicative of an antinociceptive effect. 3. I.c.v. injection of equimolar doses of BK-related peptides, Lys-BK and Met-Lys-BK, also induced an increase of DPEST, but the magnitude of the effect was not as intensive as that induced by BK, when the maximum increase of DPEST was considered. The peptide T-kinin induced a short lasting and weak antinociceptive effect. 4. The B1 agonist, des-Arg9-BK (8 nmol) induced a significant antinociceptive effect, but this was not as intensive as that induced by BK. 5. The B2 antagonist D-Arg0-Hyp3-Thi5,8-D-Phe7-BK (D-Arg0) competitively antagonized the BK-induced antinociception. Likewise, Hyp3-Thi5,8-D-Phe7-BK (Hyp) also antagonized BK effect. However, the compound Thi5,8-D-Phe7-BK (Thi), initially considered a pure BK antagonist, induced an antinociceptive effect, supporting previous observations that this peptide can also act as a partial agonist. 6. It is concluded that the dose-dependent antinociceptive effect induced by i.c.v. injection of BK is mediated by the stimulation of brain B2 receptors.

Asunto(s)

Analgésicos/farmacología , Bradiquinina/farmacología , Receptores de Bradiquinina/efectos de los fármacos , Animales , Bradiquinina/agonistas , Bradiquinina/antagonistas & inhibidores , Antagonistas de los Receptores de Bradiquinina , Pulpa Dental/fisiología , Relación Dosis-Respuesta a Droga , Estimulación Eléctrica , Inyecciones Intraventriculares , Masculino , Umbral del Dolor/efectos de los fármacos , Ratas , Ratas Wistar

RESUMEN

In this study, we characterized the cardiovascular effects produced by microinjection of doses in the femtomole range of bradykinin (BK) into the nucleus tractus solitarii of male Wistar rats (230-280 g, n = 120) anesthetized with urethane (1.2 g/kg, i.p.). Microinjections of BK (1, 10, 100 fmol, and 1 and 10 pmol, in 50 nl) or vehicle (NaCl, 0.9%) were made by using a triple-barreled glass micropipette into the medial nTS (0.4 mm anterior, 0.3 mm lateral to the obex and 0.3 mm deep from the dorsal surface). Microinjection of BK produced a shallow dose-dependent decrease in mean arterial pressure and heart rate reaching -18 +/- 6 mmHg and -21 +/- 5 beats/min, with the dose of 10 pmol. The peripheral mechanism of these effects, tested in animals treated with methylatropine (2 mg/kg, i.v.), or propranolol (2 mg/kg, i.v.) or prazosin (30 micrograms/kg, i.v.), was shown to be mainly dependent on an increase in vagal efferent activity for bradycardia and a decrease in sympathetic activity for hypotension. In order to investigate the receptor subtype involved in these effects, BK was microinjected into the nTS before and after the injection of the B1 receptor antagonist, Des-Arg9-Leu8-BK (DALBK) (11.5 pmol) or before and after the B2 receptor antagonist, HOE-140 (7.7 pmol). The cardiovascular effects of BK were significantly attenuated by the microinjection of HOE-140 and DALBK into the nTS. The effect of BK microinjected into the nTS on the baroreflex modulation was also investigated. While BK produced a significant facilitation of the baroreflex, HOE-140 and DALBK produced a significant attenuation of the baroreceptor control of heart rate. Taken together, the data presented in this study indicate the nTS as a site, in the central nervous system, for the modulatory effect of BK on the central cardiovascular control.

Asunto(s)

Bradiquinina/farmacología , Hemodinámica/efectos de los fármacos , Núcleo Solitario/fisiología , Anestesia , Animales , Barorreflejo/efectos de los fármacos , Presión Sanguínea/efectos de los fármacos , Bradiquinina/administración & dosificación , Antagonistas de los Receptores de Bradiquinina , Relación Dosis-Respuesta a Droga , Frecuencia Cardíaca/efectos de los fármacos , Masculino , Microinyecciones , Nervios Periféricos/efectos de los fármacos , Presorreceptores/efectos de los fármacos , Ratas , Ratas Wistar , Receptores de Bradiquinina/efectos de los fármacos

RESUMEN

The gene encoding a putative mouse bradykinin B1 receptor was cloned from a genomic library by low stringency screening. Analysis of two isolated clones revealed a region which contains an open reading frame uninterrupted by introns and encodes a 334 amino acid protein, which exhibits seven potential transmembrane domains and is 68% identical to the human and rabbit bradykinin B1 receptors. Lipopolysaccharide-treatment induces B1 receptor transcripts in the heart, liver, and lung. Stable expression of the coding region in COS-7 cells resulted in high levels of binding sites for the specific B1 ligand des-ARG10 kallidin (Kd = 1.3 nM; Bmax = 51 fmol/mg protein). The rank order of affinity of the receptor for the agonists and antagonists was: des-Arg9BKdes-Arg9Leu8BKdes- Arg10kallidin >> Hoe-140=bradykinin. Functional coupling of the cloned receptor was demonstrated by the dose-dependent effects of des-Arg(9)BK on the extracellular acidification rate in stably transfected COS-7 cells. This effect was not produced by bradykinin and could be blocked by the B1 antagonist des-Arg9Leu8BK.

Asunto(s)

Receptores de Bradiquinina/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Clonación Molecular , Cartilla de ADN/genética , Humanos , Cinética , Ratones , Datos de Secuencia Molecular , ARN Mensajero/genética , ARN Mensajero/metabolismo , Conejos , Receptor de Bradiquinina B1 , Receptores de Bradiquinina/efectos de los fármacos , Receptores de Bradiquinina/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Homología de Secuencia de Aminoácido , Distribución Tisular

RESUMEN

1. This study analyses the receptors mediating the effects of bradykinin (BK) and analogues on neurogenic twitch contractions of the mouse isolated vas deferens evoked, in the presence of captopril (3 microM), by electrical field stimulation with trains of 4 rectangular 0.5 ms pulses of supramaximal strength, delivered at a frequency of 10 Hz every 20 s. 2. BK (0.1-300 nM) induced a graded potentiation of twitches, with an EC50 (geometric mean and 95% confidence limits) of 4.5 nM (1.7-11.6) and an Emax of 315 +/- 19 mg per 10 mg of wet tissue (n = 6). Similar results were obtained in tissues challenged with Lys-BK, [Hyp3]-BK, Met,Lys-BK and the selective B2 receptor agonist [Tyr(Me)8]-BK (0.1-300 nM). 3. The selective B2 receptor antagonists, Hoe 140 (1-10 nM) and NPC 17731 (3-30 nM), caused graded rightward shifts of the curve to BK-induced twitch potentiation, yielding apparent pA2 values of 9.65 +/- 0.09 and 9.08 +/- 0.13, respectively, and Schild plot slopes not different from 1. Both antagonists (100 nM) failed to modify similar twitch potentiations induced by substance P (3 nM) or endothelin-1 (1 nM). Preincubation with the selective B1 receptor antagonist, [Leu8,des-Arg9]-BK (1 microM), increased the potentiating effect of BK on twitches at 30-300 nM. 4. In contrast to BK, the selective B1 receptor agonist, [des-Arg9]-BK (0.3-1000 nM) reduced the amplitude of twitches in a graded fashion, with an IC50 of 13.7 nM (10.4-16.1) and an Imax of 175 +/- 11 mg (n = 4). The twitch depression induced by [des-Arg9]-BK (300 nM) was not affected by Hoe140 (30nM) or NPC 17731 (100nM), but was abolished by the selective B1 receptor antagonist,[Leu8,des-Arg9]-BK (1 microM), which did not modify the twitch inhibitory effect of clonidine (1 nM) or morphine (300 nM).5. In non-stimulated preparations, BK (100 nM) also potentiated, in a Hoe 140-sensitive (10 nM)manner, the contractions induced by ATP (100 microM), but not by noradrenaline (10 microM), whereas[des-Arg9]-BK (300 nM) did not modify the contractions induced by either agonist.6. It is concluded that the mouse vas deferens expresses both B1 and B2 receptors, which modulate sympathetic neurotransmission in opposing ways. Neurogenic contractions are inhibited by stimulation of possibly prejunctional B, receptors, whereas activation of B2 receptors increases twitch contractions,in part by amplifying the responsiveness of the smooth muscle cells to the sympathetic co-transmitter ATP.

Asunto(s)

Bradiquinina/farmacología , Receptores de Bradiquinina/efectos de los fármacos , Transmisión Sináptica/efectos de los fármacos , Conducto Deferente/inervación , Adenosina Trifosfato/farmacología , Animales , Bradiquinina/análogos & derivados , Bradiquinina/antagonistas & inhibidores , Captopril/farmacología , Relación Dosis-Respuesta a Droga , Estimulación Eléctrica , Masculino , Ratones , Contracción Muscular/efectos de los fármacos , Músculo Liso/efectos de los fármacos , Músculo Liso/inervación , Conducto Deferente/efectos de los fármacos

RESUMEN

1. The mechanisms underlying bradykinin (BK)-mediated contractions in strips of guinea-pig gallbladder (GPG) were examined by use of selective bradykinin (BK) receptor agonists and antagonists. 2. Addition of BK and related kinins (0.1 pM-10 microM) after 2 h of equilibration of the preparation caused graded contractions characterized by two distinct phases: high affinity (0.1 pM-1 nM) and low affinity (3 nM-10 microM). The rank order of potency for the first phase (mean EC50, pM) was: BK (1.36) = Hyp3-BK (1.44) = Lys-BK (1.54) > Tyr8-BK (2.72) > Met-Lys-BK (4.30). The rank order of potency for the second phase (mean EC50, nM, at concentration producing 50% of the contraction caused by 80 mM KCl) was: Hyp3-BK (8.95) > Met-Lys-BK (12.78) > Tyr8-BK (33.75) > Lys-BK caused by 80 mM KCl) was: Hyp3-BK (8.95) > Met-Lys-BK (12.78) > Tyr8-BK (33.75) > Lys-BK (60.92) > BK (77.35). The contractile responses (g of tension) to 3 microM of BK (the highest concentration tested) were: Hyp3-BK, 1.76 +/- 0.09; BK, 1.65 +/- 0.12; Lys-BK, 1.45 +/- 0.13; Tyr8-BK, 1.36 +/- 0.15 and Met-Lys-BK, 1.36 +/- 0.15. The selective B1 agonist, des-Arg9-BK, caused only a weak contraction with maximal response (0.21 +/- 0.05 g), which corresponded to approximately 10% of that induced by BK. 3. BK-induced contraction in GPG was inhibited by indomethacin (3 microM) or ibuprofen (30 microM), and was partially reduced by phenidone (30 microM), but was not affected by atropine (1 JM), nicardipine (1 gM),Ca2+-free medium plus EGTA, dazoxiben (30 nM), L-655,240 (10 nM, a selective receptor antagonist ofthromboxane A2), MK-571 (0.1 microM, a selective leukotriene D4 receptor antagonist), tetrodotoxin(0.3microM), CP 96,345 (0.3 microM, a NK1 receptor antagonist), mepyramine (1 microM), glibenclamide (1 microM), H-7(3 microM), staurosporine (100 nM), or phorbol 12-myristate 13-acetate (1 microM). However, BK-induced contractions in GPG maintained in Ca2+-free medium were markedly attenuated by ryanodine (10microM).4. Prostaglandin E2, prostaglandin F2alpha or U46619 (0.1 nM to 100microM), caused concentration-dependent contractions in GPG with mean EC50s of 3.1 microM; 1.7 microM and 0.47 nM and maximal responses of1.36 +/-0.15; 1.32 +/- 0.20 and 0.96 +/- 0.09 g, respectively.5. The selective B2 receptor antagonists, Hoe 140, NPC 17731 and NPC 17761 (0.01 -1 microM), caused concentration-dependent displacements to the right of the contractile concentration-response curve for BK. The selective B1 receptor antagonist, des-Arg9-[Leu8]-BK (1 microM), did not affect BK-induced GPG contraction.6. These data suggest that both high and low affinity BK responses in GPG are mediated by activation of B2 receptors, and that BK-mediated contraction in GPG depends on the release of intracellular Ca2+sources sensitive to ryanodine. In addition, BK-induced contraction in GPG is mediated by release of proinflammatory eicosanoid(s) derived from the cyclo-oxygenase pathway from arachidonic acid metabolism unrelated to thromboxane A2, and seems not to be coupled to activation of a protein kinase C-dependent mechanism.

Asunto(s)

Bradiquinina/farmacología , Vesícula Biliar/efectos de los fármacos , Animales , Bradiquinina/análogos & derivados , Dinoprostona/farmacología , Relación Dosis-Respuesta a Droga , Femenino , Cobayas , Ibuprofeno/farmacología , Técnicas In Vitro , Indometacina/farmacología , Masculino , Contracción Muscular/efectos de los fármacos , Músculo Liso/efectos de los fármacos , Compuestos de Potasio/farmacología , Receptores de Bradiquinina/efectos de los fármacos

RESUMEN

1. Using the classical pharmacological criteria recommended by Schild, namely the order of potency of selective agonists (e.g., bradykinin, desArg9-bradykinin, [Hyp3]BK and [Aib7]BK) and the apparent affinity of competitive antagonists (e.g., DArg[Hyp3,DPhe7,Leu8]BK and WIN 64338), we have attempted to characterize B2 receptor subtypes. It has been shown that vascular tissues (e.g., dog carotid and renal arteries, rabbit jugular vein and rabbit aorta) are very sensitive to kinin agonists and antagonists (pD2 and pA2 values for BK and HOE 140 on B2 receptors are 8.5-10.1 and 9.2-9.4, respectively, and for desArg9BK and desArg9[Leu8]BK on B1 receptors they are 7.3-8.6 and 7.3-7.8, respectively). Mechanisms of action of kinins differ between pharmacological preparations. Kinin may act directly on the smooth muscle (e.g., rabbit jugular vein and rabbit aorta) as well as indirectly through other endogenous mediators such as nitric oxide (EDRF) (e.g., dog carotid and renal arteries) and prostaglandins (e.g., dog renal artery). 2. Pharmacological analysis of rabbit jugular vein (RJV) and guinea pig ileum (GPI) has revealed different sensitivities to certain synthetic analogs of BK and to competitive B2 receptor antagonists between the two tissues. 3. Agonist order of potency ([Hyp3]BK > BK > [Aib7]BK) obtained for RJV differed from that obtained for GPI (BK > or = [Aib7]BK > [Hyp3]BK). Competitive antagonists such as DArg[Hyp3, DPhe7, Leu8]BK and WIN 64338 discriminate in favor of B2A (RJV) and B2B (GPI) receptor subtypes, respectively. These data demonstrate the existence of B2 receptor subtypes. Correlation between data obtained in the present study and those reported for binding to the human B2 receptor support the view that the human receptor is similar to that of the rabbit.

Asunto(s)

Cininas/fisiología , Receptores de Bradiquinina/fisiología , Receptores de Superficie Celular/fisiología , Animales , Aorta/efectos de los fármacos , Aorta/fisiología , Bioensayo , Antagonistas de los Receptores de Bradiquinina , Arterias Carótidas/efectos de los fármacos , Arterias Carótidas/fisiología , Perros , Cobayas , Humanos , Íleon/efectos de los fármacos , Íleon/fisiología , Venas Yugulares/efectos de los fármacos , Venas Yugulares/fisiología , Cininas/farmacología , Contracción Muscular/efectos de los fármacos , Músculo Liso/efectos de los fármacos , Músculo Liso/fisiología , Músculo Liso Vascular/efectos de los fármacos , Músculo Liso Vascular/fisiología , Conejos , Receptores de Bradiquinina/clasificación , Receptores de Bradiquinina/efectos de los fármacos , Receptores de Superficie Celular/efectos de los fármacos , Arteria Renal/efectos de los fármacos , Arteria Renal/fisiología

RESUMEN

1. The B1 receptor agonist des-Arg9-BK does not induce mechanical hyperalgesia when injected into the rat knee joint at 1-100 nmol, or thermal hyperalgesia when injected intravenously up to 1 mumol/kg. 2. Bradykinin (BK), administered into the joint, (1 nmol-1 mumol) induces a mechanical hyperalgesia, which is maximal by 4 h. Co-administration of BK with Hoe 140 (5 pmol) blocked development of the hyperalgesia, whereas des-Arg9-Leu8-BK (0.5 nmol) had no effect. Intravenous BK had no effect on thermal paw withdrawal latencies up to 1 mumol/kg. 3. Following joint inflammation induced by local Freund's complete adjuvant, intraarticular injection of des-Arg9-BK (0.05-10 nmol) and BK (0.5-100 nmol) caused a reduction in tolerated load. Co-administration of des-Arg9-Leu8-BK (0.5 nmol) with des-Arg9-BK (0.5 nmol) blocked development of the hyperalgesia, whereas Hoe 140 (5 pmol) had no effect. BK (1 nmol)-induced hyperalgesia was blocked by Hoe 140 but not des-Arg9-Leu8-BK. 4. Following UV irradiation of the paw, intravenous des-Arg9-BK and BK reduced paw withdrawal latencies to a noxious thermal stimulus indicating thermal hyperalgesia. The latency reduction induced by des-Arg9-BK and BK was prevented with co-administration of des-Arg9-Leu8-BK 200 nmol/kg, but not with Hoe 140 0.5 mumol/kg. 5. After interleukin-1 beta pre-treatment (1 unit into the joint or paw) des-Arg9-BK induced both thermal and mechanical hyperalgesia. Co-administration of des-Arg9-Leu8-BK 0.5 nmol with des-Arg9-BK 0.5 nmol into the joint prevented development of hyperalgesia and co-administration of des-Arg9-Leu8-BK (200 nmol/kg, iv) with des-Arg9-BK 10 nmol/kg prevented reduction of thermal withdrawal latencies. 6. These data suggest that after an inflammatory insult B1 receptors may play a role in the transduction of nociceptive information.

Asunto(s)

Bradiquinina/análogos & derivados , Hiperalgesia/fisiopatología , Animales , Artritis/inducido químicamente , Bradiquinina/farmacología , Antagonistas de los Receptores de Bradiquinina , Adyuvante de Freund , Hiperalgesia/etiología , Inyecciones Intraarticulares , Inyecciones Intravenosas , Interleucina-1/farmacología , Ratas , Tiempo de Reacción , Receptores de Bradiquinina/agonistas , Receptores de Bradiquinina/efectos de los fármacos , Rayos Ultravioleta

RESUMEN

The increase in sensitivity of guinea pig preparations to bradykinin (BK) due to stretching occurring with time after mounting was studied by determining the time course of changes in the cell membrane potential, measured with intracellular microelectrodes. A sustained hyperpolarizing effect of BK, which was observed in recently mounted preparations, became transient after 120 min, when it was followed by depolarization, which was much more evident after 4 h of stretching. As a consequence, a parallel increase in the contractile response to BK was also observed. The hyperpolarizing effect was due to the opening of Ca(2+)-dependent K+ channels sensitive to apamin, since BK dose-response curves done within 1 h of mounting were shifted to the left, becoming similar to dose-response curves obtained 4 h after mounting of the guinea pig ileum preparation. These results were specific for BK, since the potentiating effect of apamin was not observed for acetylcholine. Our results show that the activation of B2 receptors by BK in the isolated guinea pig ileum induce a dual effect--hyperpolarization and depolarization--and that the increase in the contractile response consequent to stretching is probably due to the inactivation of apamin-sensitive Ca(2+)-dependent K+ channels.

Asunto(s)

Contracción Muscular/fisiología , Músculo Liso/fisiología , Receptores de Bradiquinina/fisiología , Animales , Apamina/farmacología , Bradiquinina/farmacología , Canales de Calcio/efectos de los fármacos , Canales de Calcio/fisiología , Cobayas , Potenciales de la Membrana/efectos de los fármacos , Potenciales de la Membrana/fisiología , Microelectrodos , Contracción Muscular/efectos de los fármacos , Músculo Liso/efectos de los fármacos , Canales de Potasio/efectos de los fármacos , Canales de Potasio/fisiología , Receptores de Bradiquinina/efectos de los fármacos , Factores de Tiempo