Title 11. CHOLINERGIC AND ANTICHOLINERGIC DRUGS AND NEUROMUSCULAR BOCKERS.pdf ✅

PHARMD GURU Page 1 CHOLONERGIC SYSTEM CHOLINERGIC TRANSMISSION: Acetylcholine (ACh) is the neurotransmitter in the cholinergic system. The neurons that synthesize, store and release ACh are called cholinergic neurons. SYNTHESIS OF ACETYLCHOLINE: Choline enters the cholinergic neuron by carrier-mediated transport, where it reacts with acetyl-CoA with the help of choline acetyltransferase (ChAT) to form ACh. The ACh is then stored in storage vesicles. It is released into the synaptic deft when an action potential reaches the nerve terminals. The released ACh interacts with cholinergic receptors on effector cell and activates them. In the synaptic deft, the ACh is rapidly hydrolysed by acetylcholinesterase (AChE) enzyme. CHOLINERGIC AND ANTICHOLINERGIC DRUGS NEUROMUSCULAR BLOCKERS Fig: Synthesis, storage and fate of released Ach at the cholinergic nerve endings, ChAT, Choline acetyltransferase, AChe, acetylcholineserase.

PHARMD GURU Page 3 TABLE 2.2 CHARACTERISTICS OF MUSCARINIC AND NICOTINIC RECEPTOR SUBTYPES: RECEPTOR TYPE(S) CELLULAR RESPONSE FUNCTIONAL RESPONSE M1 & M3 ↑Inositol triphosphate(IP3) and ↑Diacylglycerol (DAG)  Increases learning and memory.  Promotes glandular secretion and smooth muscle contraction. M2 ↓Cyclic adenosine monophosphate(Camp), opening of K+ channels HYPERPOLARIZATION  Depresses SA node  Depresses AV node  Decreases atrial and ventricular contraction NN Opening of Ion channels (Na+, K+) DEPOLARIZATION  Release of adrenaline and noradrenaline from adrenal medulla NM Opening of ion channels (Na+, K+)  Depolarization  Skeletal muscle contraction