RESUMEN
OBJECTIVE AND DESIGN: This study attempted to clarify the roles of endothelins and mechanisms associated with ETA/ETB receptors in mouse models of colitis. MATERIALS AND METHODS: Colitis was induced by intracolonic administration of 2,4,6-trinitrobenzene sulfonic acid (TNBS, 1.5 mg/animal) or dextran sulfate sodium (DSS, 3%). After colitis establishment, mice received Atrasentan (ETA receptor antagonist, 10 mg/kg), A-192621 (ETB receptor antagonist, 20 mg/kg) or Dexamethasone (1 mg/kg) and several inflammatory parameters were assessed, as well as mRNA levels for ET-1, ET-2 and ET receptors. RESULTS: Atrasentan treatment ameliorates TNBS- and DSS-induced colitis. In the TNBS model was observed reduction in macroscopic and microscopic score, colon weight, neutrophil influx, IL-1ß, MIP-2 and keratinocyte chemoattractant (KC) levels, inhibition of adhesion molecules expression and restoration of IL-10 levels. However, A192621 treatment did not modify any parameter. ET-1 and ET-2 mRNA was decreased 24 h, but ET-2 mRNA was markedly increased at 48 h after TNBS. ET-2 was able to potentiate LPS-induced KC production in vitro. ETA and ETB receptors mRNA were increased at 24, 48 and 72 h after colitis induction. CONCLUSIONS: Atrasentan treatment was effective in reducing the severity of colitis in DSS- and TNBS-treated mice, suggesting that ETA receptors might be a potential target for inflammatory bowel diseases.
Asunto(s)
Colitis/inmunología , Antagonistas de los Receptores de la Endotelina A/farmacología , Endotelina-2/inmunología , Pirrolidinas/farmacología , Animales , Atrasentán , Células Cultivadas , Colitis/inducido químicamente , Colitis/tratamiento farmacológico , Colitis/patología , Colon/efectos de los fármacos , Colon/inmunología , Colon/patología , Citocinas/inmunología , Sulfato de Dextran , Selectina E/inmunología , Antagonistas de los Receptores de la Endotelina A/uso terapéutico , Antagonistas de los Receptores de la Endotelina B/farmacología , Endotelina-1/genética , Endotelina-1/inmunología , Endotelina-2/genética , Leucocitos/efectos de los fármacos , Leucocitos/inmunología , Masculino , Ratones Endogámicos BALB C , Infiltración Neutrófila/efectos de los fármacos , Selectina-P/inmunología , Peroxidasa/inmunología , Pirrolidinas/uso terapéutico , ARN Mensajero/metabolismo , Receptor de Endotelina A/genética , Receptor de Endotelina A/inmunología , Receptor de Endotelina B/genética , Receptor de Endotelina B/inmunología , Ácido TrinitrobencenosulfónicoRESUMEN
BACKGROUND AND PURPOSE: The effects of centrally administered cannabinoids on body core temperature (Tc) and the contribution of endogenous cannabinoids to thermoregulation and fever induced by lipopolysaccharide (LPS) (Sigma Chem. Co., St. Louis, MO, USA) were investigated. EXPERIMENTAL APPROACH: Drug-induced changes in Tc of male Wistar rats were recorded over 6 h using a thermistor probe (Yellow Springs Instruments 402, Dayton, OH, USA) inserted into the rectum. KEY RESULTS: Injection of anandamide [(arachidonoylethanolamide (AEA); Tocris, Ellisville, MO, USA], 0.01-1 microg i.c.v. or 0.1-100 ng intra-hypothalamic (i.h.), induced graded increases in Tc (peaks 1.5 and 1.6 degrees C at 4 h after 1 microg i.c.v. or 10 ng i.h.). The effect of AEA (1 microg, i.c.v.) was preceded by decreases in tail skin temperature and heat loss index (values at 1.5 h: vehicle 0.62, AEA 0.48). Bell-shaped curves were obtained for the increase in Tc induced by the fatty acid amide hydrolase inhibitor [3-(3-carbamoylphenyl)phenyl] N-cyclohexylcarbamate (Cayman Chemical Co., Ann Arbor, MI, USA) (0.001-1 ng i.c.v.; peak 1.9 degrees C at 5 h after 0.1 ng) and arachidonyl-2-chloroethylamide (ACEA; Tocris) (selective CB(1) agonist; 0.001-1 microg i.c.v.; peak 1.4 degrees C 5 h after 0.01 microg), but (R,S)-(+)-(2-Iodo-5-nitrobenzoyl)-[1-(1-methyl-piperidin-2-ylmethyl)-1H-indole-3-yl] methanone (Tocris) (selective CB(2) agonist) had no effect on Tc. AEA-induced fever was unaffected by i.c.v. pretreatment with 6-Iodo-2-methyl-1-[2-(4-morpholinyl)ethyl]-1H-indole-3-yl](4-methoxyphenyl) methanone (Tocris) (selective CB(2) antagonist), but reduced by i.c.v. pretreatment with N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (AM251; Tocris) (selective CB(1) antagonist). AM251 also reduced the fever induced by ACEA or LPS. CONCLUSIONS AND IMPLICATIONS: The endogenous cannabinoid AEA induces an integrated febrile response through activation of CB(1) receptors. Endocannabinoids participate in the development of the febrile response to LPS constituting a target for antipyretic therapy.
Asunto(s)
Regulación de la Temperatura Corporal/efectos de los fármacos , Temperatura Corporal/efectos de los fármacos , Moduladores de Receptores de Cannabinoides/fisiología , Fiebre/metabolismo , Receptor Cannabinoide CB1/agonistas , Animales , Ácidos Araquidónicos/farmacología , Cannabinoides/farmacología , Endocannabinoides , Fiebre/etiología , Lipopolisacáridos/farmacología , Masculino , Piperidinas/farmacología , Alcamidas Poliinsaturadas/farmacología , Pirazoles/farmacología , Ratas , Ratas Wistar , Receptor Cannabinoide CB1/antagonistas & inhibidores , Receptor Cannabinoide CB1/fisiología , Receptor Cannabinoide CB2/agonistas , Receptor Cannabinoide CB2/antagonistas & inhibidores , Receptor Cannabinoide CB2/fisiologíaRESUMEN
The kinin system can contribute distinctly to the sensory changes associated with different models of nerve injury-induced neuropathic pain. This study examines the roles of kinin B(1) and B(2) receptor-operated mechanisms in alterations in nociceptive responses of rats submitted to unilateral L5/L6 spinal nerve ligation (SNL) injury. Behavioural responses to ipsilateral hind paw stimulation with acetone (evaporation-evoked cooling), radiant heat (Hargreaves method) or von Frey hairs revealed that SNL rats developed long-lasting cold allodynia (from Days 3 to 40 post-surgery, peak on Day 6), heat hyperalgesia (stable peak from Days 9 to 36) and tactile allodynia (stable peak from Days 3 to 51). SNL rats manifested nocifensive responses to intraplantar injections on Day 12 of the selective B(1) receptor agonist des-Arg(9)-bradykinin (DABK) and augmented responses to the selective B(2) receptor agonist bradykinin (BK; each at 0.01-1nmol/paw). Systemic treatment of SNL rats with des-Arg(9)-Leu(8)-BK or HOE 140 (peptidic B(1) and B(2) receptor antagonists, respectively; 0.1-1mumol/kg, i.p.) selectively blocked responses triggered by DABK and BK (1nmol/paw) and alleviated partially and transiently established cold allodynia, heat hyperalgesia and (to a lesser extent) tactile allodynia. Western blot analysis revealed enhanced expression of kinin B(1) and B(2) receptor protein in ipsilateral L4-L6 spinal nerve and hind paw skin samples collected on Day 12 after SNL surgery. These results indicate that peripheral pronociceptive kinin B(1) and B(2) receptor-operated mechanisms contribute significantly to the maintenance of hind paw cold and mechanical allodynia and heat hyperalgesia induced by L5/L6 SNL in rats.
Asunto(s)
Neuralgia/fisiopatología , Receptor de Bradiquinina B1/fisiología , Receptor de Bradiquinina B2/fisiología , Nervios Espinales/fisiología , Animales , Conducta Animal , Bradiquinina/análogos & derivados , Bradiquinina/farmacología , Antagonistas del Receptor de Bradiquinina B1 , Antagonistas del Receptor de Bradiquinina B2 , Modelos Animales de Enfermedad , Vías de Administración de Medicamentos , Lateralidad Funcional , Hiperalgesia/fisiopatología , Ligadura , Masculino , Dimensión del Dolor , Umbral del Dolor/efectos de los fármacos , Ratas , Ratas Wistar , Receptor de Bradiquinina B1/agonistas , Receptor de Bradiquinina B2/agonistas , Nervios Espinales/efectos de los fármacos , Nervios Espinales/lesiones , Factores de TiempoRESUMEN
Changes in responsiveness of the vas deferens and urinary bladder to bradykinin (BK) receptor agonists (Tyr8-BK and des-Arg9-BK), substance P (SP), and endothelin-1 (ET-1) were assessed 8 weeks after streptozotocin (STZ)-induced diabetes. Preparations from control or STZ-treated (60 mg/kg i.p.) male rats were tested for contractile and neurogenic twitch potentiating (TP, in VD only) effects of all four agonists (1 nM to 0.3 or 3 microM). In diabetic VD, contractile effects of Tyr8-BK, des-Arg9-BK, and SP were enhanced, but ET-1 effects were unchanged. In contrast, TP by des-Arg9-BK was unaffected, that by Tyr8-BK was decreased, and those by SP and ET-1 were increased. In diabetic UB, only contractions to des-Arg9-BK and SP were enhanced. Following insulin replacement (human, 1-3 U/day s.c.), starting 1 week after STZ, TP induced by Tyr8-BK and des-Arg9-BK in VD were further inhibited, but all other changes in both preparations were reversed at least partially. Insulin treatment of nondiabetic rats, however, also affected VD (but not UB) responsiveness, such that contractions to Tyr8-BK and TP by ET-1 were increased, but TP by Tyr8-BK was decreased. Thus, STZ-induced type I diabetes causes important alterations in responsiveness of non-vascular smooth muscle tissues of the rat to BK, SP, and ET-1. Long term insulin replacement, at doses normalising glycaemia, effectively reversed most changes in VD or UB responsiveness, but it is unclear if this is truly due to blocking of STZ-induced changes, since the treatment also affected responsiveness of nondiabetic tissues.
Asunto(s)
Diabetes Mellitus Experimental/fisiopatología , Insulina/farmacología , Péptidos/farmacología , Vejiga Urinaria/fisiología , Conducto Deferente/efectos de los fármacos , Animales , Relación Dosis-Respuesta a Droga , Endotelina-1/farmacología , Endotelina-1/fisiología , Técnicas In Vitro , Masculino , Péptidos/fisiología , Ratas , Ratas Wistar , Receptores de Bradiquinina/agonistas , Receptores de Bradiquinina/fisiología , Sustancia P/farmacología , Sustancia P/fisiología , Vejiga Urinaria/efectos de los fármacos , Conducto Deferente/fisiologíaRESUMEN
OBJECTIVE: Compare the antipyretic effects of dipyrone and indomethacin. MATERIALS AND METHODS: Fever was induced in rats by i. v. LPS or i. c. v. interleukins (IL), prostaglandins (PG), arachidonic acid (AA), pre-formed pyrogenic factor (PFPF), tumour necrosis factor-alpha (TNF-alpha) or corticotrophin releasing hormone (CRH). Dipyrone and indomethacin were administered i.p., arginine vasopressin V1-receptor antagonist, d(CH2)5 Tyr(Me)AVP, into the ventral septal area. Cyclooxygenase (COX-1/-2) blocking activity was assessed in transfected COS-7 cells. CRH release from isolated hypothalami was determined by ELISA. RESULTS: Indomethacin or dipyrone reduced LPS, IL-1beta, IL-6 or TNF-alpha induced fever and CRH release from rat hypothalamus. Only dipyrone inhibited IL-8, PFPF or PGF2alpha fever. Only indomethacin inhibited fever induced by AA or IL-1beta, plus AA. Neither antipyretic affected fever caused by PGE2 or CRH. d(CH2)5Tyr(Me)AVP only blocked antipyresis induced by indomethacin. Dipyrone at a very high concentration (10 mM) inhibited only COX-1, while indomethacin (0.1 microM) blocked COX-1 and COX-2 in COS-7 cells. CONCLUSION: The antipyretic effect of dipyrone differs from that of indomethacin in that it does not depend on AVP release or inhibition of PG synthesis.
Asunto(s)
Analgésicos no Narcóticos/farmacología , Dipirona/farmacología , Indometacina/farmacología , Animales , Células COS , Hormona Liberadora de Corticotropina/metabolismo , Cricetinae , Inhibidores de la Ciclooxigenasa/farmacología , Dinoprostona/farmacología , Relación Dosis-Respuesta a Droga , Interleucina-1/farmacología , Interleucina-6/farmacología , Lipopolisacáridos/toxicidad , Masculino , Ratas , Ratas WistarRESUMEN
The present study investigated hind paw oedema mediated by bradykinin B(1) and B(2) receptors in streptozotocin-diabetic rats. Paw oedema induced by intraplantar (i.pl.) injection of bradykinin or the selective bradykinin B(2) receptor agonist, Tyrosine(8)-bradykinin ([Tyr(8)]bradykinin) (both 3 nmol/paw), was significantly reduced at 4 weeks after streptozotocin treatment (34 +/- 8% and 40 +/- 7%). At 6 weeks after streptozotocin, when paw oedema caused by substance P or prostaglandin E(2) (both 10 nmol/paw) was unchanged, inhibition of bradykinin B(2) receptor-mediated oedema was maximal (66 +/- 6% and 72 +/ -2%, for bradykinin and [Tyr(8)]bradykinin, respectively). The selective bradykinin B(1) receptor agonist, [des-Arg(9)]bradykinin (100 nmol/paw), induced only slight paw oedema in non-diabetic controls. Responses to [des-Arg(9)]bradykinin were markedly enhanced 8 weeks after streptozotocin (from 0.09 +/- 0.01 to 0.38 +/- 0.05 ml), less so at 10 weeks (0.22 +/- 0.03 ml), and returning to basal values at 12 weeks (0.11 +/- 0.03 ml). Treatment with insulin protamine zinc (1-3 U/day/7 weeks, s.c.) did not reverse the inhibition of responses to [Tyr(8)]bradykinin or the potentiation of responses to [des-Arg(9)]bradykinin seen at 8 weeks. Thus, streptozotocin-induced diabetes induces long-lasting alterations in oedematogenic responsiveness to kinins in the rat, characterized by marked reduction of oedema involving activation of bradykinin B(2) receptors, associated with enhancement of bradykinin B(1) receptor-mediated oedema.
Asunto(s)
Bradiquinina/análogos & derivados , Diabetes Mellitus Experimental/fisiopatología , Edema/patología , Receptores de Bradiquinina/fisiología , Animales , Bradiquinina/farmacología , Antagonistas de los Receptores de Bradiquinina , Dinoprostona/farmacología , Edema/inducido químicamente , Miembro Posterior , Hipoglucemiantes/farmacología , Insulina de Acción Prolongada/farmacología , Masculino , Ratas , Ratas Wistar , Receptor de Bradiquinina B1 , Receptor de Bradiquinina B2 , Sustancia P/farmacología , Factores de TiempoRESUMEN
We have examined the responsiveness of strips of rabbit gallbladder (RGB) to endothelin (ET) receptor agonists, and its susceptibility to blockade by selective antagonists. Endothelin-1 (ET-1; 0.1-100.0 nM) caused graded tonic contractions with a CK50 (concentration causing response equivalent to 50% of KCl 80 mM) of 3.4 nM and EH (response to highest concentration) of 186 +/- 22, being 40-fold less potent than cholecystokinin-8 (CCK-8), 103-fold more potent than carbachol, but equipotent to ET-3, sarafotoxin S6c (S6c) and IRL 1620. The selective ETA receptor antagonists BQ-123 (3 microM) and A-127722-5 (0.3 microM) did not block responses to ET-1, but BQ-123 depressed responses to 30-100 nM ET-3 by about 35%. The ETB receptor antagonist BQ-788 (1 microM) shifted the curve to S6c by only fivefold. In rabbit aorta and at these same concentrations, BQ-123 and A-127722-5 markedly shifted (> or = 100-fold) the curve for ET-1-induced contraction, whereas BQ-788 shifted that for S6c 40-fold. Higher concentrations of all three antagonists contracted the RGB. Thus, although RGB responses to ETs and selective ETB receptor agonists seem to be largely mediated via ET, receptors, they are remarkably insensitive to blockade by both selective ETA and ETB receptor antagonists, as previously reported in the guinea pig gallbladder. Finally, through yet unknown mechanisms, high concentrations of ET receptor antagonists induce marked RGB contractions. It remains to be seen whether this finding is predictive of adverse biliary tract side-effects of such drugs in the clinic.
Asunto(s)
Endotelina-1/farmacología , Vesícula Biliar/efectos de los fármacos , Contracción Muscular/efectos de los fármacos , Receptores de Endotelina/fisiología , Animales , Femenino , Vesícula Biliar/fisiología , Técnicas In Vitro , Masculino , Oligopéptidos/farmacología , Péptidos Cíclicos/farmacología , Piperidinas/farmacología , Conejos , Receptor de Endotelina A , Receptor de Endotelina BRESUMEN
Endothelins (ETs) potently contract guinea pig gallbladder (GPGB) via endothelin-A and -B (ETA and ETB) receptors. This study assesses the possible participation of eicosanoids in the mediation of responses of the GPGB (Krebs' solution, 37 degrees C, 0.5 g load) triggered through each receptor type. Indomethacin (INDO; 5.6 microM) shifted the curve to endothelin-1 (ET-1) (0.1-100 nM) to the right, enhancing the CK50 (concentration causing 50% of response to KCl 80 mM) from 0.9 to 6.8 nM and reducing its EH (response to 100 nM) from 170 +/- 13 to 123 +/- 9 (% of response to 80mM KCl). INDO strongly depressed responses to sarafotoxin S6c (S6c; control CK50 0.9 nM), reducing its EH from 108 +/- 5 to 21 +/- 4. Neither BQ-123 nor BQ-788 (1 microM) changed responses to ET-1, but each markedly reduced responsiveness to ET-3 (control: CK50 of 9.7 nM and EH of 153 +/- 14; BQ-123: approximately = 100 nM and 44 +/- 12; BQ-788 approximately = 100 nM and 65 +/- 18). In the presence of BQ-123, INDO further depressed responses to ET-3 (EH 26 +/- 6), whereas in the presence of BQ-788, such responses were strongly enhanced (EH 126 +/- 9). These findings strongly suggest that contractions of GPGB caused via ETB receptors are mediated to a large extent by contractile eicosanoids, whereas those caused (at least by ET-3) via ETA receptors are limited by relaxant eicosanoids. The cellular sources and nature of the eicosanoids released by ETs remain to be established.
Asunto(s)
Endotelinas/farmacología , Vesícula Biliar/efectos de los fármacos , Indometacina/farmacología , Contracción Muscular/efectos de los fármacos , Animales , Femenino , Vesícula Biliar/fisiología , Cobayas , Técnicas In Vitro , Masculino , Oligopéptidos/farmacología , Péptidos Cíclicos/farmacología , Piperidinas/farmacología , Receptor de Endotelina A , Receptor de Endotelina B , Receptores de Endotelina/fisiologíaRESUMEN
OBJECTIVE: Investigate the role of endothelins in leukocyte recruitment in allergic and non allergic inflammation. METHODS: Pleurisy was induced in mice by intrathoracic injection of ovalbumin (OVA; in sensitized animals), E. coli LPS, carrageenan, Mycobacterium bovis (BCG) or zymosan. Animals were treated with BQ-123 or BQ-788 (1.5-150 pmol/cavity), or intravenously with bosentan (30 mg/kg). RESULTS: None of the ET receptor antagonists modified early neutrophil recruitment (at 4 h) induced by OVA, LPS, carrageenan, BCG or zymosan or plasma leakage caused by carrageenan or zymosan. Mononuclear and eosinophil accumulation triggered by OVA were reduced by BQ-123 (150 pmol/cavity) or bosentan (68 and 43% inhibition of eosinophilia), but unaffected by BQ-788. BQ-123 and bosentan also inhibited LPS increases in neutrophil (by 67 and 40%) and eosinophil (by 63 and 74%) at 24 h. CONCLUSIONS: Endothelins, acting via ETA receptors, play a role in late eosinophil and neutrophil accumulation (24 h), but not in the acute (4 h) neutrophilic response.
Asunto(s)
Endotelinas/fisiología , Eosinófilos/fisiología , Neutrófilos/fisiología , Pleuresia/patología , Animales , Antagonistas de los Receptores de Endotelina , Recuento de Leucocitos , Lipopolisacáridos/farmacología , Masculino , Ratones , Infiltración Neutrófila , Oligopéptidos/farmacología , Ovalbúmina , Péptidos Cíclicos/farmacología , Piperidinas/farmacología , Pleuresia/inducido químicamente , Proteínas/metabolismo , Receptor de Endotelina A , Receptor de Endotelina B , Receptores de Endotelina/efectos de los fármacos , Receptores de Endotelina/fisiologíaRESUMEN
Endothelin-1 causes ET(A) receptor-mediated enhancement of capsaicin-induced nociception in mice. We have assessed if this hyperalgesic effect of endothelin-1 is also accompanied by other pro-inflammatory effects, namely nociception and oedema, and characterized the endothelin ET receptors involved. Intraplantar (i. pl.) hind-paw injection of endothelin-1 (0.3 - 30 pmol) induced graded nociceptive responses (accumulated licking time: vehicle, 20. 5+/-3.3 s; endothelin-1 at 30 pmol, 78.1+/-9.8 s), largely confined to the first 15 min. Endothelin-1 (1 - 10 pmol) potentiated ipsilateral capsaicin-induced (0.1 microgram, i.pl.; at 30 min) nociception (vehicle, 40.2+/-2.6 s; endothelin-1 at 10 pmol, 98.4+/-5.8 s, but 30 pmol was inactive), and caused oedema (increase in paw weight 5 min after capsaicin: vehicle, 46.3+/-2.3 mg; endothelin-1 at 30 pmol, 100.3+/-6.1 mg). Selective ET(B) receptor agonists sarafotoxin S6c (up to 30 pmol) and IRL 1620 (up to 100 pmol) were inactive, whereas endothelin-3 (up to 30 pmol) induced only modest oedema. ET(A) receptor antagonists BQ-123 (1 nmol, i.pl. ) or A-127722-5 (6 micromol kg(-1), i.v.) prevented all effects of endothelin-1 (10 pmol), but the ET(B) receptor antagonist BQ-788 (1 or 10 nmol, i.pl.) was ineffective. BQ-788 (10 nmol, i.pl.) unveiled hyperalgesic effects of 30 pmol endothelin-1 and endothelin-3. Sarafotoxin S6c (30 pmol, i.pl.) did not modify endothelin-1-induced (10 pmol) nociception or oedema, but abolished hyperalgesia. Thus, endothelin-1 triggers ET(A) receptor-mediated nociception, hyperalgesia and oedema in the mouse hind-paw. Simultaneous activation of ET(B) receptors by endothelin-1 or selective agonists can limit the hyperalgesic, but not the nociceptive or oedematogenic, effects of the peptide.
Asunto(s)
Edema/inducido químicamente , Endotelina-1/farmacología , Hiperalgesia/inducido químicamente , Nociceptores/efectos de los fármacos , Receptores de Endotelina/agonistas , Receptores de Endotelina/efectos de los fármacos , Animales , Atrasentán , Capsaicina , Edema/patología , Antagonistas de los Receptores de Endotelina , Endotelinas/farmacología , Masculino , Ratones , Oligopéptidos/farmacología , Fragmentos de Péptidos/farmacología , Péptidos Cíclicos/farmacología , Piperidinas/farmacología , Pirrolidinas/farmacología , Receptor de Endotelina A , Receptor de Endotelina B , Venenos de Víboras/farmacologíaRESUMEN
Endothelins participate in different aspects of inflammatory reactions, including edema formation and eosinophil accumulation in allergic reaction. In this study, we demonstrated a role for endogenous endothelins in eosinophil and T lymphocyte recruitment and cytokine secretion in a murine model of allergic inflammation. Intrathoracic stimulation with endothelin-1 triggered a neutrophil accumulation at 4 h, concomitant with an increase of CD4+ and CD8+ T lymphocyte populations. Antigen challenge in sensitized animals leads to an increase in eosinophil and mononuclear cell numbers at 24 h. Treatment with ETA receptor antagonist (BQ123) inhibited antigen-induced eosinophil and mononuclear cell migration, whereas the selective ETB receptor antagonist BQ-788 was ineffective. The latter effect of BQ-123 was due to inhibition of CD4+ and CD8+ T lymphocytes. Treatment with BQ-123 also inhibited interleukin-5 levels in the exudate and plasma as well as intracellular staining of interleukin-4, interleukin-5, and interferon-gamma in CD4+ lymphocytes. These findings suggest that endogenous endothelins contribute to allergic inflammation by modulating lymphocyte recruitment and cytokine production.
Asunto(s)
Quimiotaxis de Leucocito , Endotelina-1/fisiología , Subgrupos Linfocitarios/patología , Pleuresia/inmunología , Hipersensibilidad Respiratoria/inmunología , Animales , Bosentán , Linfocitos T CD4-Positivos/química , Antagonistas de los Receptores de Endotelina , Humanos , Interferón gamma/análisis , Interleucina-4/análisis , Interleucina-5/análisis , Ionomicina/farmacología , Masculino , Ratones , Ratones Endogámicos C57BL , Monensina/farmacología , Oligopéptidos/farmacología , Ovalbúmina/inmunología , Ovalbúmina/toxicidad , Péptidos Cíclicos/farmacología , Piperidinas/farmacología , Pleuresia/metabolismo , Pleuresia/patología , Receptor de Endotelina A , Receptor de Endotelina B , Receptores de Endotelina/fisiología , Hipersensibilidad Respiratoria/metabolismo , Hipersensibilidad Respiratoria/patología , Sulfonamidas/farmacología , Acetato de Tetradecanoilforbol/farmacologíaRESUMEN
In the guinea-pig ileum, both sarafotoxin S6c and IRL1620 (Suc-[Glu9,Ala11,15]endothelin-1-(8-21) induced a concentration-dependent biphasic effect (relaxation and contraction), but distinct tachyphylaxis of the tissue. Cross-tachyphylaxis and additivity experiments evidenced distinct receptors for these agonists. BQ-123 (cyclo[D-Trp-D-Asp-Pro-D-Val-Leu]), an endothelin ET(A) receptor antagonist, did not affect the response induced by either agonist. PD145065 [Ac-(D-Bhg-Leu-Asp-Ile-Ile-Trp) (D-Bhg = 5H-dibenzyl[a,d]cycloheptene-10,11-dihydroglycine)], an endothelin ET(A)/ET(B) receptor antagonist, inhibited the contractions induced by IRL1620 and sarafotoxin S6c in competitive and noncompetitive manner, respectively. RES-701-1 [cyclic(Gly1-Asp9)(Gly-Asn-Trp-His-Gly-Thr-Ala-Pro-Asp-Trp-P he-Phe-Asn-Tyr-Tyr-Trp)], an endothelin ET(B1) receptor antagonist, inhibited both components of the response induced by IRL1620, whereas it inhibited mainly the relaxation induced by low sarafotoxin S6c doses. Apamin and suramin had different effects towards the agonists. Our results suggest that two endothelin ET(B) receptors with distinct signal transduction mechanism mediate the biphasic response: (1) the endothelin ET(B1) receptor: sensitive to RES-701-1 and PD145065 and (2) the endothelin ET(B2) receptor: less sensitive to RES-701-1 and PD145065.
Asunto(s)
Endotelinas/farmacología , Contracción Muscular/efectos de los fármacos , Músculo Liso/efectos de los fármacos , Fragmentos de Péptidos/farmacología , Receptores de Endotelina/fisiología , Taquifilaxis , Venenos de Víboras/farmacología , Animales , Apamina/farmacología , Relación Dosis-Respuesta a Droga , Interacciones Farmacológicas , Antagonistas de los Receptores de Endotelina , Femenino , Cobayas , Íleon/efectos de los fármacos , Técnicas In Vitro , Contracción Isométrica/efectos de los fármacos , Masculino , Relajación Muscular/efectos de los fármacos , Receptores de Endotelina/agonistas , Venenos de Serpiente/química , Suramina/farmacologíaRESUMEN
1. The influence of endothelin receptor antagonists on febrile responses to E. coli lipopolysaccharide (LPS), interleukin-1beta (IL-1beta), tumour necrosis factor-alpha (TNF-alpha) and endothelin-1 (ET-1) was assessed in conscious rats. 2. Intravenous (i.v.) LPS (5.0 microg kg(-1)) markedly increased rectal temperature to a peak of 1.30 degrees C over baseline at 2.5 h. Pretreatment with the mixed endothelin ET(A)/ET(B) receptor antagonist bosentan (10 mg kg(-1), i.v.) or the selective endothelin ET(B) receptor antagonist BQ-788 (N-cis-2,6-dimethylpiperidinocarbonyl-L-gamma-methylleucyl-D -1-methoxycarboyl-D-norleucine; 3 pmol, into a lateral cerebral ventricle-i.c.v.) reduced the peak response to LPS to 0.90 and 0.75 degrees C, respectively. The selective endothelin ET(A) receptor antagonist BQ-123 (cyclo[D-Trp-D-Asp-Pro-D-Val-Leu]; 3 pmol, i.c.v.) was ineffective. 3. Increases in temperature caused by IL-1beta (180 fmol, i.c.v.), TNF-alpha (14.4 pmol, i.c.v.) or IL-1beta (150 pmol kg(-1), i.v.) were unaffected by BQ-788 (3 pmol, i.c.v.). 4. Central injection of endothelin-1 (0.1 to 3 fmol, i.c.v.) caused slowly-developing and long-lasting increases in rectal temperature (starting 2 h after administration and peaking at 4-6 h between 0.90 and 1.15 degrees C) which were not clearly dose-dependent. The response to endothelin-1 (1 fmol, i.c.v.) was prevented by BQ-788, but not by BQ-123 (each at 3 pmol, i.c.v.). Intraperitoneal pretreatment with the cyclo-oxygenase inhibitor indomethacin (2 mg kg(-1)), which partially reduced LPS-induced fever, did not modify the hyperthermic response to endothelin-1 (3 fmol, i.c.v.). 5. Therefore, central endothelin(s) participates importantly in the development of LPS-induced fever, via activation of a prostanoid-independent endothelin ET(B) receptor-mediated mechanism possibly not situated downstream from IL-1beta or TNF-alpha in the fever cascade.
Asunto(s)
Fiebre/inducido químicamente , Lipopolisacáridos/farmacología , Receptores de Endotelina/fisiología , Animales , Antagonistas de los Receptores de Endotelina , Escherichia coli/química , Indometacina/farmacología , Inyecciones Intravenosas , Interleucina-1/farmacología , Masculino , Ratas , Ratas Wistar , Factor de Necrosis Tumoral alfa/farmacologíaRESUMEN
The influence of endothelin-1 on nociception induced by capsaicin was assessed in the mouse hindpaw. Local endothelin-1 injection (1 to 20 pmol/paw) 30 min prior to ipsilateral injection of capsaicin (0.1 microg/paw) increased, in a graded fashion, the time spent licking the injected paw. Maximal hyperalgesia was obtained with 10 pmol/paw of endothelin-1 (capsaicin-induced hindpaw licking time increased from 43 +/- 3 s to 114 +/- 7 s, n = 6), but no hyperalgesia was evident following 30 pmol/paw of endothelin-1. The selective endothelin ET(B) receptor agonists sarafotoxin S6c (< or = 30 pmol/paw) and IRL 1620 (i.e., Suc[Glu9,Ala11,15]endothelin-1-(10-21); < or = 100 pmol/paw) failed to induce hyperalgesia. Local treatment with BQ-123 (i.e., cyclo[DTrp-DAsp-Pro-DVal-Leu] 1 nmol/paw selective endothelin ET(A) receptor antagonist), 10 min before endothelin-1 (10 pmol/paw), fully blocked the hyperalgesic response, whereas similar treatment with the selective endothelin ET(B) receptor antagonist BQ-788 (i.e., N-cis-2,6-dimethylpiperidinocarbonyl-L-gamma-methylleucyl-D- 1-methoxy-carboyl-D-norleucine) was ineffective. Intravenous injection of bosentan (17 and 52 micromol/kg a non-peptidic mixed endothelin ET(A)/ET(B) receptor antagonist) or BMS 182874 (i.e., 5-[dimethylamino]-N-[3,4-dimethyl-5-isoxazolyl]-1-naphthalenesulph onamide; 10 and 30 micromol/kg; a non-peptidic selective endothelin ET(A) receptor antagonist), 1 h before endothelin-1, inhibited its hyperalgesic effect in a graded fashion and abolished the response at the higher doses. None of the antagonists modified nociception induced by capsaicin alone or the hyperalgesia induced by local injection of 5-hydroxytryptamine (5-HT; 2 nmol/paw, 30 min before capsaicin). Hyperalgesia induced by 5-HT was abolished by simultaneous injection of endothelin-1 or the endothelin ET(B) receptor agonist IRL 1620 (each at 30 pmol/paw). Therefore, local endothelin-1 exerts a dual influence in this model: at low doses it causes endothelin ET(A) receptor-mediated hyperalgesia (i.e., it potentiates capsaicin-induced nociception), whereas at higher doses it induces an anti-hyperalgesic effect against 5-HT which seems to be mediated via distinct endothelin ET (possibly ET(B)) receptors.
Asunto(s)
Analgesia , Endotelina-1/farmacología , Hiperalgesia/tratamiento farmacológico , Animales , Bosentán , Capsaicina , Compuestos de Dansilo/farmacología , Relación Dosis-Respuesta a Droga , Antagonistas de los Receptores de Endotelina , Endotelina-1/administración & dosificación , Endotelinas/farmacología , Miembro Posterior , Hiperalgesia/inducido químicamente , Masculino , Ratones , Oligopéptidos/farmacología , Fragmentos de Péptidos/farmacología , Péptidos/farmacología , Péptidos Cíclicos/farmacología , Piperidinas/farmacología , Receptor de Endotelina A , Receptor de Endotelina B , Receptores de Endotelina/agonistas , Serotonina/farmacología , Sulfonamidas/farmacología , Venenos de VíborasRESUMEN
Endothelin-1 (ET-1; 3-100 nM) caused graded tonic contractions and enhanced neurogenic contractions in rat field-stimulated seminal vesicle. At 100 nM, ET-1 increased nerve-mediated responses by 350 +/- 74 mg/100 mg wet tissue (almost 100% potentiation), whereas sarafotoxin S6c was ineffective. The potentiation of neurogenic responses by ET-1 was virtually abolished by the ETA receptor antagonist BQ-123 (1 microM; c. 95% inhibition) but was not modified by the ETB receptor antagonist BQ-788 (1 microM). Responses to field stimulation were inhibited by tetrodotoxin (0.1 microM; 100%), guanethidine (GTD; 5 microM, 75%), prazosin (PRA; 0.1 microM, 90%), desensitization of P2x purinoceptors with alpha,beta-methylene-ATP (mATP; 10 microM, 50%), or atropine (ATR; 0.1 microM, 40%). ET-1-induced potentiation of neurogenic contractions was not modified by prior incubation with indomethacin (5.6 microM), ATR, or PRA, but mATP and GTD reduced the effects of 100 nM ET-1 to 189 +/- 76 and 5 +/- 7 mg/100 mg wet tissue, respectively (n = 6-8). Therefore, ET-1 enhances nerve-mediated responses of this tissue by selectively potentiating the purinergic component of sympathetic neurotransmission. This action, which is independent of the eicosanoid-cycloxygenase pathway, is mediated via ETA receptors and, at least in part, by enhancement of motor responses to ATP.
Asunto(s)
Endotelina-1/farmacología , Receptores Purinérgicos/efectos de los fármacos , Vesículas Seminales/inervación , Sistema Nervioso Simpático/efectos de los fármacos , Transmisión Sináptica/efectos de los fármacos , Animales , Estimulación Eléctrica , Técnicas In Vitro , Masculino , Ratas , Ratas Wistar , Receptor de Endotelina B , Receptores de Endotelina/agonistas , Vesículas Seminales/efectos de los fármacos , Vasoconstrictores/farmacología , Venenos de Víboras/farmacologíaRESUMEN
This study assessed the possible local nociceptive and hyperalgesic properties of endothelin-1 (ET-1) in the rat knee-joint incapacitation test, in which animals are placed for 1 min/h on a revolving (3 rpm) metal cylinder and nociception is measured as the time the hindpaw of the injected limb was off the cylinder (i.e., paw elevation time, PET). Carrageenan (Cg; 150 micrograms/joint), E. coli LPS (1 microgram/joint), and ET-1 (120 or 240 pmol/joint) each increased PET persistently, unlike sarafotoxin S6c (120-240 pmol/joint) or PBS. ET-1 (15 and 30 pmol/joint, 30 min before) did not cause incapacitation per se but potentiated PET induced by Cg, increasing the area under the curve (AUC in arbitrary units, 0-6 h) from 105 +/- 9 to 165 +/- 10 and 169 +/- 25, respectively. Prior Cg injection (300 micrograms/joint, 72 h before) sensitized the joint to incapacitation triggered by restimulation with either Cg (300 micrograms/joint), LPS (1 microgram/joint), or ET-1 (30 pmol/joint). Treatment with bosentan (10 mg/kg i.v., 15 min before joint stimulation) did not affect PET values in naive animals to Cg or LPS, but significantly reduced the upregulated response evoked by restimulation with LPS (but not Cg), from 465 +/- 24 to 290 +/- 49 (AUC 0-12 h). Therefore, ET-1 triggers nociception and hyperalgesia in the naive knee joint of the rat, perhaps via ETA receptors. Although local endogenous ETs may not have a role in inflammatory nociception in the naive joint, they may participate in articular incapacitation induced by restimulation with LPS. This latter finding could be relevant to the etiology of pain associated with chronic arthritic diseases.
Asunto(s)
Artritis Experimental/patología , Endotelina-1/toxicidad , Miembro Posterior/patología , Hiperalgesia/inducido químicamente , Articulaciones/patología , Animales , Artritis Experimental/inducido químicamente , Bosentán , Carragenina , Antagonistas de los Receptores de Endotelina , Endotoxinas , Hiperalgesia/patología , Lipopolisacáridos , Masculino , Ratas , Ratas Wistar , Sulfonamidas/farmacología , Vasoconstrictores/farmacología , Venenos de Víboras/farmacologíaRESUMEN
The present study investigates the influence of endothelin (ET) related peptides (0.3-30 pmol/paw) on both phases of nociception and on edema induced by intraplantar injection of formalin (0.5% in 20 microL) in the mouse hind paw. The first phase of nociception (0-5 min after injection) was significantly potentiated by simultaneous injection of either ET-1 (10 or 30 pmol/paw) or ET-3 (10 pmol/paw), but not of the selective ET3 receptor agonist sarafotoxin S6c (SRTX-c; up to 30 pmol/paw). All three peptides potentiated the second phase (10-30 min after injection) of formalin-induced nociception (at 3-30, 1-30, and 10-30 pmol/paw for ET-1, ET-3, and SRTX-c, respectively), whereas only ET-1 (10 or 30 pmol/paw) effectively enhanced edema caused by formalin (30 min after injection). Histamine also potentiated all three responses triggered by formalin, but was 30- to 100-fold less potent than ET-1. Treatment with the mixed ETA/ETB receptor antagonist bosentan (10 mg/kg i.p., 1 h beforehand) did not influence nociceptive and edematogenic responses to formalin or their potentiation by histamine (3 nmol/paw), but did inhibit the potentiations induced by ET-1 (10 pmol/paw). Thus, ET-1 potentiates formalin-induced nociception and edema in the mouse. These actions are possibly mediated via ETB and ETA receptors, respectively, but their true identity and the mechanisms involved still remain to be fully elucidated.
Asunto(s)
Edema/inducido químicamente , Endotelina-1/toxicidad , Endotelina-2/toxicidad , Formaldehído/toxicidad , Nociceptores/efectos de los fármacos , Animales , Bosentán , Relación Dosis-Respuesta a Droga , Sinergismo Farmacológico , Antagonistas de los Receptores de Endotelina , Masculino , Ratones , Dimensión del Dolor , Receptor de Endotelina A , Receptor de Endotelina B , Sulfonamidas/farmacología , Venenos de Víboras/toxicidadRESUMEN
The receptors mediating guinea pig gall bladder (GPGB) contractions induced by endothelin-1 (ET-1) and related peptides were characterized using various ET receptor antagonists. As all ET-receptor agonists used, except sarafotoxin S6c (SRTX), failed to induce a clear-cut maximal response at the highest concentration tested (i.e. 100 nM), their potencies are expressed in terms of a CK50 (i.e. the concentration causing 50% of the response to 80 mM KCl). ET-1 (CK50 0.8 nM) was equipotent to ET-2 and SRTX (selective ET(B) receptor agonist), but more potent than ET-3 (5-fold) or IRL 1620 (selective ET(B) receptor agonist). BQ-123 (0.3 microM, peptidic ET(A) receptor antagonist) did not alter responses to ET-1, ET-3 or SRTX. BQ-788 (1 microM, peptidic ET(B) receptor antagonist) reduced the potency of ET-3 (9-fold at the CK50 level) and SRTX ( > 20-fold), but not ET-1. SRTX responses were unaffected by RES-701-1 (3 microM, peptidic ET(B) receptor antagonist). The combination BQ-123 (0.3 microM) plus BQ-788 (1 microM) did not modify responses to ET-1, inhibited SRTX responses similarly to BQ-788 alone and abolished ET-3 responses. Bosentan (1 microM, non-peptidic ET(A)/ET(B) receptor antagonist) reduced the potency of ET-1 (15-fold). ET-3 (9-fold) and SRTX (4-fold). In rat aorta, the antagonists blocked ET-1-induced contractions (BQ-123 and bosentan) or SRTX-induced endothelium-dependent relaxations (BQ-788, RES-701-1 and bosentan). Thus, the GPGB expresses both ET(A) and ET(B) receptors. As BQ-123 only blocked responses to ET-3 in the presence of BQ-788, there appears to be cross-talk between both receptor types. Also, the binding sites of ET-1 and ET-3 on the ET(A) receptor may not coincide entirely, as BQ-123, even in presence of BQ-788, did not affect ET-1-induced contractions.
Asunto(s)
Vesícula Biliar/metabolismo , Contracción Muscular , Receptores de Endotelina/metabolismo , Animales , Relación Dosis-Respuesta a Droga , Antagonistas de los Receptores de Endotelina , Femenino , Vesícula Biliar/efectos de los fármacos , Cobayas , Masculino , Contracción Muscular/efectos de los fármacos , Oligopéptidos/administración & dosificación , Oligopéptidos/farmacología , Péptidos/farmacología , Péptidos Cíclicos/administración & dosificación , Péptidos Cíclicos/farmacología , Piperidinas/administración & dosificación , Piperidinas/farmacología , Ratas , Receptor de Endotelina A , Receptor de Endotelina BRESUMEN
This study assessed the effects of intracerebroventricular administration of selective agonists and antagonists for tachykinin NK1 and NK2 receptors on performance of mice in the elevated plus-maze, an ethological model of anxiety. Mice were treated with either vehicle (5 microliters) or 1, 10, 100 or 500 pmol of substance P, neurokinin A, the selective NK1 receptor agonist substance P methyl ester, or the selective NK2 receptor agonist, [beta-Ala8]neurokinin A-(4-10). Other mice received similar doses of FK 888, i.e., N2-[(4R)-4-hydroxy-1-(1-methyl-1 H-indol-3-y)carbonyl-L-prolyl]-N-methyl-N-phenylmethyl-3-(2-naphthyl)-L- alaninamide, or SR 48968, i.e., (S)-N-methyl-(N-[4-acetylamine-4-phenylpiperidine)-2-(3, 4-dichlorophenyl)buthyl]benzamide, selective antagonists of tachykinin NK1 and NK2 receptors, respectively. Injections of substance P, neurokinin A, substance P methyl ester or [beta-Ala8]neurokinin A-(4-10) significantly reduced the frequency of open arm entries, and [beta-Ala8]neurokinin A-(4-10) also enhanced the percentage of entries into enclosed arms. Conversely, the NK1 antagonist FK 888 and the NK2 antagonist SR 48968 each increased the time spent in the open arms, and SR 48968 also increased the frequency of entries into the open arms. None of the tachykinin receptor agonists or antagonists modified motor performance and coordination on the rotarod apparatus or ambulation in an activity cage. Together, these results suggest that centrally administered NK1 and NK2 receptor agonists and antagonists can modulate anxiety, as evaluated in the elevated plus-maze test in mice. Stimulation of either tachykinin NK1 or NK2 receptors induces anxiogenic-like responses, whereas the reverse occurs following their blockade. The anxiolytic-like profiles of action of both tachykinin NK1 and NK2 receptor antagonists suggest that central tachykinin mechanisms are tonically involved in the modulation of anxiety.
Asunto(s)
Ansiolíticos/farmacología , Ansiedad/inducido químicamente , Ansiedad/tratamiento farmacológico , Receptores de Taquicininas/agonistas , Receptores de Taquicininas/antagonistas & inhibidores , Animales , Ansiolíticos/administración & dosificación , Ansiedad/psicología , Benzamidas/farmacología , Dipéptidos/farmacología , Relación Dosis-Respuesta a Droga , Indoles/farmacología , Inyecciones Intraventriculares , Masculino , Ratones , Actividad Motora/efectos de los fármacos , Neuroquinina A/administración & dosificación , Neuroquinina A/farmacología , Antagonistas del Receptor de Neuroquinina-1 , Piperidinas/farmacología , Equilibrio Postural/efectos de los fármacos , Receptores de Neuroquinina-1/agonistas , Receptores de Neuroquinina-2/agonistas , Receptores de Neuroquinina-2/antagonistas & inhibidores , Sustancia P/administración & dosificación , Sustancia P/farmacologíaRESUMEN
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.