<prompt> Which muscarinic receptor causes dilatation of vessels-M1M2m3m4  <response>: Ans. is c i.e., M3 o M3 receptors are found in vessels endothelium. Activation of these recepters causes vasodilatation by release of EDRF NO.o M3 receptors are unique muscarinic receptors in that their activation does not cause release of acetylcholine, rather causes relcease of EDRF NO. 