RESUMEN
BACKGROUND: In order to evaluate prognostic factors in the long-term survival of desmoid tumour patients, analysis of clinicopathological, immunohistochemical and follow-up data was performed. PATIENTS AND METHODS: Between 1969 and 1998, 54 patients underwent resection of aggressive fibromatosis (desmoid) and 33 of them (10 patients with FAP and 23 sporadic) were followed-up with a median time of 130 months (range 10-355 months). Additionally, immunohistochemical analysis of the desmoid tumours using Ki-67 was performed. RESULTS: In univariate analysis, curative resection (R0) (p<0.001) and low proliferation of Ki-67 (p=0.002) were of significant positive prognostic value concerning disease-free survivaL R0 and absence of Ki-67 staining were significantly associated with each other (p=0.004). CONCLUSION: Ki-67 seems to serve as a predictive marker concerning disease-free survival of desmoid tumour patients. In patients presenting with Ki-67 positive desmoids, which are unlikely to be resected in a curative manner, alternative treatment (e.g. sulindac) may be preferable.
Asunto(s)
Fibromatosis Agresiva/metabolismo , Antígeno Ki-67/biosíntesis , Poliposis Adenomatosa del Colon/metabolismo , Poliposis Adenomatosa del Colon/patología , Adulto , Anciano , Anciano de 80 o más Años , Supervivencia sin Enfermedad , Femenino , Fibromatosis Agresiva/patología , Humanos , Inmunohistoquímica , Masculino , Persona de Mediana Edad , Estudios RetrospectivosRESUMEN
The effect of single administrations of aerosolized heparin, low molecular weight heparin (LMWH) and the linear polyanionic molecule, polyglutamic acid (PGA) were examined on antigen-induced airway hyperresponsiveness and leukocyte accumulation in neonatally immunized rabbits. Adult litter-matched NZW rabbits immunized within 24 h of birth with Alternaria tenuis antigen were treated with heparin, LMWH or PGA prior to or following antigen challenge (Alternaria tenuis). For each drug-treated group, a parallel group of rabbits were treated with the appropriate vehicle. In all groups, airway responsiveness to inhaled histamine and bronchoalveolar lavage (BAL) was performed 24 h prior to and following antigen challenge. Basal lung function in terms of resistance (R(L)) and dynamic compliance (C(dyn)) and acute bronchoconstriction was unaltered by pre-treatment with heparin, LMWH or PGA compared to their respective vehicles 24 h prior to or following antigen challenge. In vehicle-treated animals, airway hyperresponsiveness to inhaled histamine was indicated by an increase in the maximal responses of the cumulative concentration-effect curves to histamine and reductions in R(L)PC(50) and C(dyn)PC(35) values 24 h following antigen challenge. Heparin and LMWH given prior to antigen challenge significantly inhibited the development of airway hyperresponsiveness, whereas PGA did not. When given following antigen challenge, all three drugs failed to inhibit the development of airway hyperresponsiveness. Eosinophil and neutrophil cell numbers in BAL fluid increased significantly 24 h following antigen challenge. Heparin, LMWH and PGA failed to inhibit the increase in cell numbers following antigen challenge whether given prior to or following antigen challenge.
Asunto(s)
Broncoconstricción/efectos de los fármacos , Heparina/farmacología , Leucocitos/efectos de los fármacos , Enfermedad Aguda , Análisis de Varianza , Animales , Lavado Broncoalveolar , Relación Dosis-Respuesta a Droga , Femenino , Heparina de Bajo-Peso-Molecular/farmacología , Histamina/farmacología , Hipersensibilidad , Inmunización , Leucocitos/fisiología , Pulmón/efectos de los fármacos , Pulmón/fisiología , Masculino , Ácido Poliglutámico/farmacología , ConejosRESUMEN
This study has examined the effects of animal age on the contractile responsiveness and inositol phosphate-generating capacities of guinea-pig (0-104 weeks) and rat (4-104 weeks) isolated tracheal smooth muscle in response to endothelin-1 (ET-1). The influence of animal age on the specific binding of [125I]ET-1 to guinea-pig and rat isolated tracheal tissue was also examined. The potency (pD2) of ET-1 was three to four times greater in tracheal tissue taken from 4-week-old rats than in similar tissue from 12- to 32-week-old animals, although maximum response (Emax) was not significantly altered. Neither pD2 nor Emax were influenced by ageing in epithelium-intact guinea-pig tracheal preparations. In contrast, removal of the airway epithelium significantly increased the contractile potency of ET-1 by two- to three-fold in tissue from animals of 6-20 weeks of age, but not in tissue from newborn animals. Significant falls in specific [125I]ET-1 grain density with ageing were demonstrated during the maturation phase in both species. In the rat, the decrease between 4 and 12 weeks was reflected in the fall in ET-1 potency at 12 weeks. However, the age-associated reduction in airway smooth muscle ET receptor number in the guinea-pig was not mirrored by significant changes in sensitivity to ET-1, suggesting the presence of a functional receptor reserve. ET-1 (1 nM) caused significant increases in intracellular inositol phosphates, with levels generally higher in rat than in guinea-pig trachea. ET-1-induced inositol phosphate accumulation decreased significantly with respect to animal age in both guinea-pig and rat isolated tracheal tissue. However, this was not correlated with changes in contractile pD2 or Emax. For example, in both rat and guinea-pig, the smallest ET-1-induced increases in intracellular inositol phosphates were measured in airway smooth muscle from the oldest animals tested, although tissue sensitivity to ET-1 was stable in both species after 12 weeks of age. These data suggest that relatively low levels of inositol phosphates were required to elicit Emax, consistent with the presence of more than one signal transduction process.
Asunto(s)
Envejecimiento/fisiología , Endotelina-1/fisiología , Tráquea/fisiología , Animales , Autorradiografía , Endotelina-1/metabolismo , Endotelina-1/farmacología , Epitelio/metabolismo , Epitelio/fisiología , Cobayas , Técnicas In Vitro , Fosfatos de Inositol/metabolismo , Masculino , Contracción Muscular/efectos de los fármacos , Contracción Muscular/fisiología , Músculo Liso/efectos de los fármacos , Músculo Liso/metabolismo , Músculo Liso/fisiología , Ensayo de Unión Radioligante , Ratas , Ratas Wistar , Tráquea/metabolismoRESUMEN
We examined the influence of animal age on the functional response of guinea-pig (0-156 weeks) and rat (4-136 weeks) isolated tracheal tissue to beta-adrenoceptor agonists. In addition, the binding density and affinity of [125I]iodocyanopindolol ([125I]CYP) binding to tracheal tissue was examined with respect to animal age. Significant age-related changes in isoprenaline potency were observed in tracheal ring preparations taken from animals during the early maturation phase of animal growth in the guinea-pig and rat. In addition, in rat isolated tracheal tissue, age-related decreases in fenoterol potency were observed during senescence, but not maturation. The changes in the functional responsiveness of tracheal tissue were not reflected by changes in the binding density or affinity for [125I]cyanopindolol ([125I]CYP) of beta-adrenoceptors, or in changes in specific autoradiographic grain density over smooth muscle tissue. In both guinea-pig and rat, no significant age-related changes in the influence of catechol-O-methyl transferase (COMT) or of extraneuronal uptake inhibition were detected. This study has demonstrated significant age-related changes in the responsiveness of guinea-pig and rat isolated tracheal tissue to beta-adrenoceptor agonists that were not related to changes in the density or affinity of the beta-adrenoceptor population or in the activity of COMT or extraneuronal uptake. The possibility of age-related changes in receptor-signal transduction coupling should be explored.
Asunto(s)
Agonistas Adrenérgicos beta/farmacología , Envejecimiento/fisiología , Yodocianopindolol/metabolismo , Músculo Liso/fisiología , Receptores Adrenérgicos beta/fisiología , Tráquea/fisiología , Animales , Autorradiografía , Catecol O-Metiltransferasa/fisiología , Cricetinae , Fenoterol/farmacología , Técnicas In Vitro , Isoproterenol/farmacología , Músculo Liso/efectos de los fármacos , Unión Proteica , Ensayo de Unión Radioligante , Ratas , Análisis de Regresión , Tráquea/efectos de los fármacosRESUMEN
The influence of age on muscarinic cholinoceptor-mediated contraction and inositol phosphate accumulation was examined in rat and guinea-pig isolated tracheal tissue. Significant age-related changes in the sensitivity of guinea-pig tracheal tissue to acetylcholine, but not carbachol, were observed in the early maturation phase of growth with a 3.3-fold increase in potency between birth and 2 weeks of age followed by a 3.2-fold fall in potency between 2 and 12 weeks of age. Further ageing did not significantly change the potency of acetylcholine or carbachol. Whilst acetylcholinesterase inhibition caused a significant increase in acetylcholine potency, this was independent of animal age. In rat isolated tracheal tissue, contractile responses to both acetylcholine and carbachol remained unchanged with respect to animal age. Significant age-related decreases in inositol phosphate accumulation were observed in response to carbachol in the guinea-pig and rat and to acetylcholine in guinea-pig but not rat isolated tracheal tissue. This study has demonstrated significant age-related changes in the responsiveness of isolated tracheal tissue to carbachol and acetylcholine which were also species-specific.
Asunto(s)
Envejecimiento/fisiología , Fosfatos de Inositol/farmacología , Contracción Muscular/efectos de los fármacos , Músculo Liso/efectos de los fármacos , Receptores Muscarínicos/fisiología , Tráquea/fisiología , Acetilcolina/farmacología , Animales , Carbacol/farmacología , Inhibidores de la Colinesterasa/farmacología , Cricetinae , Fosfatos de Inositol/farmacocinética , Masculino , RatasRESUMEN
The influence of animal age on the responsiveness of guinea-pig and rat isolated tracheal smooth muscle to the non-selective inhibitors of phosphodiesterase, theophylline and papaverine and to the adenylyl cyclase and soluble guanylyl cyclase activators, forskolin and sodium nitroprusside respectively, was examined. Significant age-related decreases in the potencies of theophylline and papaverine were observed across the age ranges in guinea-pig (2.8- and 3.4-fold decreases respectively) and rat (1.9- and 2.6-fold decreases respectively) trachea, suggesting age-related falls in the activity of phosphodiesterase in these tissues. However, maximum relaxant responses (E(max)) to these agents were not altered with increasing animal age. The relaxant potency of sodium nitroprusside also decreased 4.4-fold across the age range in guinea-pig isolated trachea but not in rat isolated tracheal tissue, suggesting age-related falls in soluble guanylyl cyclase activity in guinea-pig trachea. In contrast, neither forskolin potency nor E(max)changed significantly with increasing age in either guinea-pig or rat tracheal tissue. The present data indicate that ageing in both guinea-pigs and rats was associated with decreased relaxant potency of phosphodiesterase (PDE) inhibitors rather than to changes in adenylyl cyclase activity although reduced soluble guanylyl cyclase activity was also detected in the guinea-pig.
Asunto(s)
Adenilil Ciclasas/farmacología , Envejecimiento/fisiología , Guanilato Ciclasa/farmacología , Músculo Liso/efectos de los fármacos , Inhibidores de Fosfodiesterasa/farmacología , Animales , Cobayas , Masculino , Músculo Liso/fisiología , Ratas , Ratas Wistar , Tráquea/efectos de los fármacos , Tráquea/fisiologíaRESUMEN
The effects of the muscarinic cholinoceptor antagonists atropine (non-selective), pirenzepine (M1-selective), methoctramine (M2-selective) and 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP; M3-selective) were examined on the responsiveness of guinea pig and rat tracheal tissue to acetylcholine and carbachol. Results indicate that smooth muscle contraction in isolated tracheal tissue from both species was mediated primarily by muscarinic M3 cholinoceptors. The effects of atropine, pirenzepine and 4-DAMP were similar against the contractile actions of acetylcholine and carbachol in both species and in epithelium-intact and epithelium-denuded tissue. In contrast, differences in the effects of methoctramine in antagonising contractile responses to acetylcholine and carbachol were observed between the two species and following epithelium removal in the guinea pig. Thus, whilst this study has found that tracheal smooth muscle contraction in the guinea pig and rat is mediated primarily by muscarinic M3 cholinoceptors, anomalies in the functional inositol phosphate generation results obtained with the muscarinic cholinoceptor antagonists highlight species differences in the actions of acetylcholine and carbachol in eliciting smooth muscle contraction suggesting the possible existence of functional non-M3 muscarinic cholinoceptors.
Asunto(s)
Fosfatos de Inositol/metabolismo , Antagonistas Muscarínicos/farmacología , Músculo Liso/efectos de los fármacos , Receptores Muscarínicos/fisiología , Tráquea/efectos de los fármacos , Animales , Atropina/farmacología , Diaminas/farmacología , Cobayas , Técnicas In Vitro , Masculino , Contracción Muscular/efectos de los fármacos , Contracción Muscular/fisiología , Músculo Liso/metabolismo , Músculo Liso/fisiología , Piperidinas/farmacología , Pirenzepina/farmacología , Ratas , Ratas Wistar , Receptores Muscarínicos/efectos de los fármacos , Receptores Muscarínicos/metabolismo , Tráquea/metabolismo , Tráquea/fisiologíaRESUMEN
The present study has established a method for obtaining low-frequency forced oscillation measurements of lung mechanics in the absence of neuromuscular blockade in the rat. Increasing the ventilation rate of the animals inhibited the spontaneous breathing of the animals for a short period of time; enough to make the low-frequency forced oscillation measurements of lung mechanics without the need for paralysis of the animals. Using this technique, it was possible to show that neuromuscular blockade with pancuronium bromide (0.4 mg/kg iv) resulted in a significant inhibition of methacholine responses in the parenchymal, but not the airway components of the rat lung. In studies where the animals were examined in a repeated manner, there was no significant difference in methacholine responses on day 3 compared with those obtained on day 1. Similarly, in animals that were both challenged with methacholine and lavaged, there was no significant difference in the methacholine responses or in the total and differential cell numbers obtained from the bronchoalveolar lavage fluid. Thus, this study presents a technique for obtaining low-frequency forced oscillation estimates of lung mechanics in non-paralysed rats and allows for repeated measures to be made in the same animals. In addition, this study has demonstrated that neuromuscular blockade has differential effects on methacholine responses in different parts of the lung.
Asunto(s)
Cloruro de Metacolina/farmacología , Respiración , Animales , Fenómenos Biomecánicos , Lavado Broncoalveolar , Masculino , Bloqueo Neuromuscular , Fármacos Neuromusculares no Despolarizantes/farmacología , Pancuronio/farmacología , Ratas , Ratas Endogámicas BNRESUMEN
In this chapter we have described anti-inflammatory functions of heparin distinct from its traditional anticoagulant activity. We have presented in vivo data showing heparin's beneficial effects in various preclinical models of inflammatory disease as well as discussed some clinical studies showing that the anti-inflammatory activities of heparin may translate into therapeutic uses. In vivo models that use low-anticoagulant heparins indicate that the anticoagulant activity can be distinguished from heparin's anti-inflammatory properties. In certain cases such as hypovolemic shock, the efficacy of a low-anticoagulant heparin derivative (GM1892) exceeds heparin. Data also suggest that nonconventional delivery of heparin, specifically via inhalation, has therapeutic potential in improving drug pharmacokinetics (as determined by measuring blood coagulation parameters) and in reducing the persistent concerns of systemic hemorrhagic complications. Results from larger clinical trials with heparin and LMW heparins are eagerly anticipated and will allow us to assess our predictions on the effectiveness of this drug class to treat a variety of human inflammatory diseases.
Asunto(s)
Heparina/uso terapéutico , Inflamación/tratamiento farmacológico , Enfermedad de Alzheimer/tratamiento farmacológico , Asma/tratamiento farmacológico , Colitis Ulcerosa/tratamiento farmacológico , Encefalomielitis Autoinmune Experimental/tratamiento farmacológico , Heparina/biosíntesis , Heparina/farmacología , Humanos , Inflamación/etiología , Integrinas/fisiología , Leucocitos/efectos de los fármacos , Agregación Plaquetaria/efectos de los fármacos , Daño por Reperfusión/tratamiento farmacológico , Síndrome de Dificultad Respiratoria/tratamiento farmacológico , Selectinas/metabolismo , Choque/tratamiento farmacológicoRESUMEN
Responsiveness to various contractile and relaxant agonists was assessed in tracheal preparations from guinea-pigs that had been incubated in situ at 4-37 degrees C for 0-168 h post-mortem. The potencies of histamine and acetylcholine were increased up to 168 h at 4 degrees C post-mortem and up to 24 h post-mortem at 22 degrees C. Histamine potency also increased with increasing post-mortem time at 37 degrees C. After 48 h at 22 degrees C and 8 h at 37 degrees C, responses to all spasmogens were abolished. Increases in histamine and acetylcholine potencies were similarly observed in tracheal tissue that had been removed at death and then incubated at 4 degrees C in oxygenated Krebs-bicarbonate solution for 0-168 h. The increased potency of these drugs may be explained by epithelial damage and/or loss of an epithelium-derived inhibitory factor (EpDIF). Both basal and spasmogen-stimulated increases in intracellular phosphoinositides fell with increasing time and ambient temperature post-mortem, despite the fact that contraction in response to these agonists could still be evoked. This suggests the selective failure of this signal transduction pathway and the maintenance of responsiveness via other mechanisms. The potencies and maximum effects of relaxant agonists remained unaltered in tracheal tissue with increasing time post-mortem, suggesting little change in the function of the appropriate receptor-signal transduction processes. This study has therefore demonstrated that at 4 degrees C. contractile and relaxant responses were preserved for up to 168 h post-mortem, although the modulatory influence of the epithelium on histamine and acetylcholine responses was rapidly lost.
Asunto(s)
Músculo Liso/fisiología , Fármacos Neuromusculares/farmacología , Cambios Post Mortem , Tráquea/fisiología , Acetilcolina/farmacología , Animales , Colorantes , Cobayas , Histamina/farmacología , Técnicas In Vitro , Isoproterenol/farmacología , Masculino , Músculo Liso/efectos de los fármacos , Músculo Liso/patología , Temperatura , Factores de Tiempo , Tráquea/efectos de los fármacos , Tráquea/patologíaRESUMEN
The influence of animal age was examined on the responses of guinea-pig (birth-156 weeks) and rat (4-136 weeks) isolated tracheal tissue to the spasmogens histamine, 5-hydroxytryptamine (5-HT) and potassium ions (K+) using functional and biochemical techniques. Over the ages birth-12 weeks in the guinea-pig, K+ potency decreased 1.5 fold whereas histamine potency increased 2-fold between the ages of birth-2 weeks and then declined to original levels by age 20 weeks. 5-HT potency declined over the entire age range examined, resulting in a 25.1 fold decrease between the ages of 1 and 156 weeks. In the rat, 5-HT potency remained unchanged and a small but progressive increase in K+ potency was observed with respect to animal age. Significant age-related changes in inositol phosphate accumulation were observed in both unstimulated and histamine-stimulated isolated guinea-pig tracheal smooth muscle which did not correlate with the functional changes observed in response to spasmogenic stimulation. The results describe disparate age-related changes between two species of different spasmogenic agonists with the majority of age-related changes occurring during the maturation phase of growth of the guinea-pig.
Asunto(s)
Envejecimiento/fisiología , Histamina/farmacología , Fosfatos de Inositol/farmacología , Serotonina/farmacología , Tráquea/efectos de los fármacos , Tráquea/fisiología , Animales , Cobayas , Técnicas In Vitro , Masculino , Contracción Muscular/efectos de los fármacos , Músculo Liso/efectos de los fármacos , Potasio/farmacología , Ratas , Ratas WistarRESUMEN
1. The influence of age and of region on alpha-adrenoceptor-mediated contraction to (-)-adrenaline and (-)-noradrenaline was examined in rat (4-136 weeks) and guinea-pig (2-156 weeks) isolated tracheal ring preparations with particular emphasis on the early (up to 12 weeks) maturation phase. 2. In rat tracheal rings, significant regional variation was observed with respect to maximal (-)-adrenaline-induced contraction, such that the greatest activity was seen in ring preparations from the laryngeal end of the trachea. Tracheal rings from the carinal end responded very poorly or were unresponsive to (-)-adrenaline, depending on animal age. These regional differences were seen across the age range. The potencies of (-)-adrenaline and (-)-noradrenaline remained unchanged with respect to animal age, but the maximum contractile tension that developed in response to these agonists increased with increasing animal age in all regions of the trachea. 3. In guinea-pig isolated tracheal tissue, maximum contractile responses (Emax) to (-)-adrenaline and (-)-noradrenaline remained unchanged with increasing animal age. In addition, there was no evidence for a region-dependence in the responsiveness of tracheal tissue to alpha-adrenoceptor-mediated contraction in this species. 4. In both guinea-pig and rat isolated tracheal tissue, alpha-adrenoceptor-mediated contraction appeared to involve the activation of alpha1-adrenoceptors.
Asunto(s)
Agonistas alfa-Adrenérgicos/farmacología , Envejecimiento/fisiología , Músculo Liso/efectos de los fármacos , Tráquea/efectos de los fármacos , Animales , Carbacol/farmacología , Cobayas , Técnicas In Vitro , Masculino , Agonistas Muscarínicos/farmacología , Potasio/farmacología , Ratas , Ratas Wistar , Tráquea/anatomía & histologíaRESUMEN
To examine cell generation in the frog retinal pigment epithelium (RPE), representative developmental stages from tail-bud to adulthood received a single injection of [3H]thymidine. Animals were killed either 24 h or several weeks later; eyes were sectioned and processed by standard autoradiographic procedures and viewed by epi-polarised illumination. The distribution of [3H]thymidine-labelled cells indicated that the RPE is formed throughout life, including in adulthood, by cell addition at the ciliary margin, matching the pattern for the neural retina. In addition, a very small number of peripapillary RPE cells underwent division but only in the adult.
Asunto(s)
Anuros/embriología , Metamorfosis Biológica/fisiología , Epitelio Pigmentado Ocular/embriología , Xenopus laevis/embriología , Animales , Anuros/crecimiento & desarrollo , Autorradiografía , Recuento de Células , Embrión no Mamífero/fisiología , Epitelio Pigmentado Ocular/crecimiento & desarrollo , Xenopus laevis/crecimiento & desarrolloRESUMEN
The current study describes the influence of age and the presence of the epithelium on guinea-pig and rat tracheal airway smooth muscle sensitivity to the spasmogens histamine, acetylcholine, carbachol and potassium. In guinea-pig trachea from animals aged 2-52 weeks the potency of each of these spasmogens decreased with increased animal age. In contrast, no age-dependent changes in the potency of acetylcholine, carbachol or potassium were seen in rat trachea. Removal of the tracheal epithelium was associated with significant increases in the potencies of histamine and acetylcholine in guinea-pig trachea and of acetylcholine in rat trachea, but not of carbachol or potassium in either species. For histamine in guinea-pig trachea, the largest potency increase (4.6-fold) occurred in tissue from 6-week-old animals, with the smallest increases in tissue from the youngest (2 weeks) and the oldest (52 weeks) animals. Thus, although the sensitivity of airway smooth muscle to this spasmogen fell between 2 and 12 weeks of age, the effect of epithelial removal on sensitivity to histamine was apparently increased during this period. Further studies are required to assess the reasons for increased histamine and acetylcholine potency in airway smooth muscle after epithelial ablation.
Asunto(s)
Envejecimiento/fisiología , Músculo Liso/efectos de los fármacos , Tráquea/efectos de los fármacos , Acetilcolina/farmacología , Análisis de Varianza , Animales , Carbacol/farmacología , Epitelio/efectos de los fármacos , Epitelio/fisiología , Cobayas , Histamina/farmacología , Masculino , Potasio/farmacología , Ratas , Ratas Wistar , Espasmo/fisiopatología , Tráquea/fisiologíaRESUMEN
1. The present study was undertaken to examine further the contribution of hypoxia to airway epithelium-dependent relaxation of rat aorta in the co-axial bioassay. 2. Endothelium-denuded rat aorta contracted with phenylephrine (0.05 microM) relaxed in a time-dependent manner (t1/2 = 8.3 +/- 0.4 min, n = 38) when the bathing solution was bubbled with 95% N2 and 5% CO2. In co-axial bioassays, the t1/2 for histamine (100 microM; guinea-pig trachea)- and methacholine (100 microM; rabbit bronchus)- induced relaxation was 1.9 +/- 0.2 min (n = 14) and 1.2 +/- 0.1 min (n = 26), respectively. 3. Hypoxia-induced relaxation was not associated with a rise in intracellular guanosine 3':5'-cyclic monophosphate (cyclic GMP). This contrasts with previous findings of an elevation in cyclic GMP associated with epithelium-dependent relaxation of rat aorta in co-axial bioassays. 4. Hypoxia-induced vascular relaxation was antagonized by the ATP-sensitive K+ channel blocker, glibenclamide (100 microM). In contrast, glibenclamide (100 microM) failed to inhibit histamine (100 microM; guinea-pig trachea)- and methacholine (0.1-100 microM; rabbit bronchus)-induced release of epithelium-derived inhibitory factor (EpDIF), in co-axial bioassays. Glibenclamide (100 microM) antagonized BRL 38227 (lemakalin), but not isoprenaline-induced relaxation of phenylephrine-contracted rat aorta. 5. These data strongly suggest that the airway epithelium-dependent relaxant responses observed in co-axial bioassays cannot be attributed to hypoxia.
Asunto(s)
Relajación Muscular/fisiología , Músculo Liso Vascular/fisiología , Fenómenos Fisiológicos Respiratorios , Animales , Aorta/efectos de los fármacos , Aorta/fisiología , Benzopiranos/farmacología , Bioensayo , Factores Biológicos/análisis , Factores Biológicos/fisiología , Cromakalim , Epitelio/fisiología , Gliburida/farmacología , Cobayas , Hipoxia/fisiopatología , Técnicas In Vitro , Isoproterenol/farmacología , Masculino , Relajación Muscular/efectos de los fármacos , Músculo Liso Vascular/efectos de los fármacos , Pirroles/farmacología , Ratas , Ratas EndogámicasRESUMEN
Three peptide components of atrial natriuretic factor (ANF) caused relaxation of carbachol-contracted guinea-pig isolated tracheal smooth muscle. These were the 1-28, 5-28 and 5-27 peptide sequences (ANF(1-28), ANF-(5-28) and ANF-(5-27)). The peptides were 10-30 times more potent in epithelium-denuded than in epithelium-intact preparations. In the absence of airway epithelium, ANF-(1-28) was the most potent relaxant (mean pD2 = 7.40 +/- 0.08), with ANF-(5-27) and ANF-(5-28) 2-3 fold less potent. The neutral endopeptidase inhibitor phosphoramidon (1 microM) increased the potency of ANF-(5-27) in both epithelium-intact and epithelium-denuded guinea-pig tracheal rings. In contrast, removal of the epithelium from rat trachea, or pretreatment with phosphoramidon (1 microM) decreased relaxant responsiveness to ANF-(5-27). Thus, in rat trachea, epithelial endopeptidase may convert ANF-(5-27) to a more active relaxant peptide. Human bronchial preparations with or without epithelium, obtained from non-diseased lung samples and from a single sample of asthmatic lung, were virtually unresponsive to ANF-(5-27). Consistent with the spasmolytic effects of ANF in guinea-pig trachea, autoradiographic analysis revealed the presence of a sparse population of specific binding sites for [125I]ANF-(1-28) over both tracheal smooth muscle and epithelium. The present study shows that the relaxant effects of atriopeptins in rat and guinea-pig airway smooth muscle were modulated by the epithelium and the activity of neutral endopeptidase. However, marked species differences in airway smooth muscle responsiveness to ANF and in the modulatory role of the airway epithelium were evident.
Asunto(s)
Factor Natriurético Atrial/farmacología , Relajación Muscular/efectos de los fármacos , Músculo Liso/efectos de los fármacos , Fragmentos de Péptidos/farmacología , Animales , Autorradiografía , Bronquios/efectos de los fármacos , Epitelio/fisiología , Cobayas , Humanos , Técnicas In Vitro , Masculino , Ensayo de Unión Radioligante , Ratas , Ratas Endogámicas , Receptores del Factor Natriurético Atrial , Receptores de Superficie Celular/metabolismo , Tráquea/efectos de los fármacosRESUMEN
1. The effects of endothelin-1 (ET-1) and of the muscarinic cholinoceptor agonist, carbachol, on [3H]-inositol phosphate ([3H]-InsP) accumulation and smooth muscle contraction were determined in rat isolated tracheal tissue. 2. ET-1 (1 microM) and carbachol (10 microM) induced significant accumulation of [3H]-InsPs in myo-[2-3H]-inositol-loaded rat tracheal segments. Several components of the tracheal wall including the airway smooth muscle band, the cartilaginous region and the intercartilaginous region generated significant levels of [3H]-InsPs in response to ET-1 and carbachol. Following stimulation with ET-1, a greater proportion of tracheal [3H]-InsPs were generated in the intercartilaginous region (49%) than in either the airway smooth muscle band (25%) or cartilaginous region (26%). However, when the respective weights of these regions is taken into account, ET-1-induced accumulation of [3H]-InsPs was greatest in the airway smooth muscle band. The tracheal epithelium did not appear to generate [3H]-InsPs in response to ET-1 or modulate either basal or ET-1-induced accumulation of [3H]-InsPs in rat tracheal segments. 3. In the rat tracheal smooth muscle band, ET-1 caused a time- and concentration-dependent accumulation of [3H]-InsPs. Concentrations of ET-1 as low as 10 nM produced significant accumulation of [3H]-InsPs (1.23 +/- 0.10 fold increase above basal levels of 295 +/- 2 d.p.m. mg-1 wet wt., n = 3 experiments). At 10 microM, the highest concentration ?tsed, ET-1 produced similar levels of [3H]-InsP accumulation (7.03 +/- 0.55 fold above basal levels, t = 5) to that produced by a maximally effective concentration of carbachol (10 microM; 7.97 +/- 0.31 fold increase above basal levels, n = 4). ET-1-induced accumulation of [3H]-InsPs was not significantly affected by indomethacin (5 microM), nordihydroguaiaretic acid (NDGA, 10 microM), WEB 2086 (10 microM) or phosphoramidon (10 microM).4. ET-1 also produced concentration-dependent contractions of epithelium-denuded rat tracheal ring preparations. The mean concentration of ET-1 producing 50% of the maximum contractile response to carbachol (EC50) was 31 nm (95% confidence limits, 20-49 nM, n = 12). The presence of an intact tracheal epithelium, indomethacin (5 microM), WEB 2086 (10 microM) and phosphoramidon (10 microM) had no significant effect on the mean EC50 for ET-1-induced contraction (n = 5). In contrast, NDGA (10 microM) inhibited ET-1- induced contractions (4.0 fold increase in mean EC50, P < 0.001, n = 5). However, this effect of NDGA did not appear to be related to inhibition of leukotriene synthesis via lipoxygenase since the leukotriene antagonist SKF 104353 did not affect ET-1-induced contractions (n = 5) and moreover, leukotriene C4 and leukotriene D4 did not contract rat isolated tracheal smooth muscle preparations (n = 4).5. The threshold concentrations of ET-1 that produced increases in smooth muscle contraction and [3H]-InsPs accumulation were similar, although the EC50 for [3H]-InsP accumulation was 2.9 fold greater than that for smooth muscle contraction. For carbachol, the EC50 for [3H]-InsP accumulation (mean ECQO = 5.0 microM, 1.2-21 microM, n = 4) was 25 fold greater than that for smooth muscle contraction(mean EC50 = 0.20 miicroM, 0.17-0.24 microM, n = 12).6. It seems likely that ET-1 has a direct effect on InsP generation in rat tracheal smooth muscle and that this is largely responsible for the spasmogenic actions of this peptide.
Asunto(s)
Endotelinas/farmacología , Fosfatos de Inositol/metabolismo , Músculo Liso/efectos de los fármacos , Animales , Carbacol/farmacología , Técnicas In Vitro , Masculino , Contracción Muscular/efectos de los fármacos , Músculo Liso/metabolismo , Ratas , Ratas Endogámicas , Tráquea/efectos de los fármacos , Tráquea/metabolismo , TritioRESUMEN
The potencies of histamine and methacholine were significantly increased by approximately 2- and 5-fold respectively in human non-diseased isolated bronchi on removal of the epithelium. In contrast, no increases in spasmogen potency were observed following epithelium removal in bronchi obtained from a sample of asthmatic human lung. The failure of epithelium removal to increase asthmatic bronchial sensitivity to histamine may have been due to a reduction in the release of an epithelium-derived inhibitory factor (EpDIF) resulting from disease-induced epithelial damage. A co-axial bioassay system in which endothelium-denuded rat aorta was used as the assay tissue was used to detect the release of a vasorelaxant EpDIF from human bronchial tissue. Histamine (100 microM) and methacholine (25 microM), in the presence of indomethacin (5 microM), reduced phenylephrine-induced tone in endothelium-denuded rat aorta in co-axial assemblies by 75 +/- 11 and 67 +/- 9% respectively. Removal of the bronchial epithelium abolished these responses, indicating that they were mediated by an EpDIF. It is possible that human airway smooth muscle is sensitive to this vasorelaxant EpDIF and that the absence of the source of this factor following epithelium removal caused the increases in sensitivity to spasmogens. Alternatively, the human bronchial epithelium may also release an EpDIF selective for airway smooth muscle.
Asunto(s)
Factores Biológicos/fisiología , Bronquios/fisiología , Animales , Asma/fisiopatología , Carbacol/farmacología , Histamina/farmacología , Humanos , Técnicas In Vitro , Indometacina/farmacología , Masculino , Compuestos de Metacolina/farmacología , Relajación Muscular/efectos de los fármacos , Músculo Liso Vascular/efectos de los fármacos , Fenilefrina/farmacología , Ratas , Ratas EndogámicasRESUMEN
1. Endothelin-1 (ET-1) binding site densities and constrictor activities were compared in airway smooth muscle preparations of human, guinea-pig, rat and mouse. 2. The mean contractile response to 0.3 microM ET-1 (measured as the % maximum response to 10 microM carbachol, % Cmax +/- s.e.mean) and the mean concentration of ET-1 producing 30% Cmax (95% confidence limits) were respectively; 85.9 +/- 5.4% and 3.4 nM (2.4-5.0) for mouse trachea (n = 11), 88.8 +/- 4.7% and 18.2 nM (11.2-25.2) for rat trachea (n = 6), 71.0 +/- 7.1% and 35.2 nM (5.4-231) for human bronchus (n = 3), and 32.3 +/- 3.0% and 241 nM (125-460) for guinea-pig trachea (n = 6). 3. Light microscopic autoradiography revealed specific [125I]-ET-1 binding sites localized to the smooth muscle band, with very low levels of binding associated with cartilage, submucosal and epithelial cells. 4. Quantitative autoradiographic analyses of the concentration-dependence of specific [125I]-ET-1 binding (0.1-2 nM) to smooth muscle revealed similar dissociation constants but markedly different specific binding site densities for the various animal species. The order of densities of specific [125I]-ET-1 binding sites was rat trachea (69.0 +/- 11.2 amol mm-2) greater than human bronchus (42.7 +/- 17.5 amol mm-2) greater than mouse trachea (28.7 +/- 2.6 amol mm-2) greater than guinea-pig trachea (8.3 +/- 1.8 amol mm-2). 5. A positive relationship between [125I]-ET-1 binding site density and ET-1 constrictor activity was observed in airway smooth muscle preparations from rat, human and guinea-pig. The greater sensitivity of mouse trachea to the constrictor actions of ET-1 was not dependent on the release of cyclo-oxygenaseor epithelium-derived constrictor substances, but may have been due to an inter-species difference in the receptor-effector system for ET-1.
Asunto(s)
Músculo Liso/efectos de los fármacos , Receptores de Superficie Celular/metabolismo , Adulto , Anciano , Animales , Autorradiografía , Bronquios/efectos de los fármacos , Endotelinas/farmacología , Cobayas , Humanos , Técnicas In Vitro , Radioisótopos de Yodo , Masculino , Ratones , Ratones Endogámicos , Persona de Mediana Edad , Contracción Muscular/efectos de los fármacos , Ratas , Ratas Endogámicas , Receptores de Endotelina , Especificidad de la Especie , Tráquea/efectos de los fármacosRESUMEN
ET-1 caused concentration-dependent, sustained contraction of all airway preparations tested and was most potent in mouse trachea, with rat trachea, human bronchus and guinea-pig trachea approximately 5, 10 and 70 fold less sensitive respectively. Human non-asthmatic and asthmatic bronchi were approximately equi-sensitive to ET-1. Quantitative light microscopic autoradiography demonstrated high levels of specific [125I]-ET-1 binding sites in airway smooth muscle of rat trachea greater than human asthmatic bronchus = human non-asthmatic bronchus greater than mouse trachea much greater than guinea-pig trachea. High levels of specific ET-1 binding were also revealed in peripheral airways and in alveolar wall tissue in human, rat and mouse lung. In a limited sample of asthmatic airway smooth muscle ET-1 receptor function and density was not elevated.