<prompt> Apa from release of EDRF, other mechanism of vasodilatory action of acetylcholine is -Direct action of cause vascular smooth muscle relaxationInhibition of nor-epinephrine release from adrenergic nerve endingsStimulation of platelet aggregationStimulation of vascular 132 receptors  <response>: Ans. is b i.e., Inhibition of nor-epinephrine release from adrenergic nerve endings o Most of the blood vessels contain cholinergic M3 receptors on endothelium but no parasympathetic nerve supply. o Exogenously administered ACh can stimulate M3 receptors which results in release of EDRF NO from endothelium that causes vasodilatation. o Vasodilation also may occur indirectly due to inhibition of NA release from nerve endings by Ach. 