Where does Ach have inhibitory effects? What types of receptors mediate each of these responses?

ACH acts on the smooth muscles,cardiac muscles and exocrine glands.The GABA acts on the messg. delivery system of the brain,Dopamine acts on the CNS and kidneys, and  Epinephrine acts on cardiac and bronchodilator adrenergic receptors.Norepinephrine acts on alpha/beta receptors and Seretonin acts on smooth muscles and gastric mucosa.

The site of action for Ach is parasympathetic.The location of receptor is muscarinic receptor.The location of muscarinic receptor is at effector cell.For example heart.Ach has inhibitory effect if the parasympathetic action is higher or same than sympathetic action which means the amount of muscuranic receptor is larger.

For example heart,the action of para and sympha is same..so,if Ach is flow in blood stream it will inhibit or slow down heart rate.Other location for Ach action are at gi tract,respiratory tract(secretion),urinary bladder(detrusor and sphincter) and also pupils and ciliary muscle.

However,the inhibitory effect based on the action of para or sympa. Becuse not all parasympathetic action to inhibit.