The parietal sheet of Bowman's capsule of rat renal glomerulus: a target of endothelin and PAF

摘要: On the basis of intracellular calcium concentration ([Ca 2+ ] i ) measurements, we have previously reported that parietal sheet Bowman's capsule was sensitive to cholinergic agonists. The aim present work investigate whether this structure could be also a target endothelin and platelet activating factor (PAF), since observed [Ca increases in response both agonists glomerulus, but which were very different from induced by carbachol. For purpose, measured on single microdissected sheets, using fura 2 microfluorescence technique compared effects maximal concentrations three (10 −7 , 10 −8 −4 M for endothelin, PAF, carbachol, respectively) under various experimental conditions. We that, like PAF induced, sheet, responses differed many respects those found with Thus, presence mM external calcium, 1) spontaneously declined basal level, whereas stationary plateau after sharp peak carbachol; 2) magnitude smaller than 3) not homologous dose-dependent desensitization. Moreover, absence carbachol response, although all apparently resulted release ions same internal pool. In additional experiments, contracted is only composed myoepithelial cells. conclusion, agonists, namely are now known act increasing inducing contractions