Effect of calcitonin gene-related peptide on the neuroeffector mechanism of sympathetic nerve terminals in rat vas deferens

摘要: Abstract In order to evaluate the mode of action calcitonin gene-related peptide (CGRP) on neuroeffector mechanism peripheral sympathetic nerve fibers, effects CGRP were tested electrical stimulated and non-stimulated preparations isolated rat vas deferens. The contractile responses, which mediated predominantly by activation postganglionic noradrenergic dose-dependently inhibited in concentrations ranging from 0.1 10 nM. inhibitory response produced high ( >2 nM ) usually returned control level at 20–30 min rarely tachyphylactic. was not modified pretreatment with −7 M propranolol or atropine. Contractions exogenous norepinephrine (NE) 5-hydroxytryptamine (5-HT) unstimulated affected a low concentration ). On other hand, contractions slightly reduced 1 after >5 ), recovered 15 constant flow washout. High also caused concentration-dependent relaxation precontracted potassium (60 mM K + solution. These results suggest that (1) may have non-specific postsynaptic plasma membrane smooth muscle cell (2) postulated receptor exists presynaptically deferens inhibit release NE during adrenergic stimulation.