the findings support the concept that guinea-pig vas deferens has a dual , cholinergic as well as adrenergic , innervation , and that the cholinergic nerves exert a dual modulatory effect on sympathetic neuro-effector function in this tissue : firstly they appear to restrict the secretion of sympathetic neurotransmitter ( via pre-junctional muscarinic receptors , on the adrenergic nerve terminals ) , and secondly they seem to enhance the excitability of the smooth muscle to sympathetic neurotransmitter ( via post-junctional muscarinic receptors , on the smooth muscle cells ) .
C1267092
smooth muscle
C1135918
smooth muscle cells