L8.Cholinergic Drugs

Question 0

By what mechanism do indirect acting cholinergic drugs have an effect?

Answer 0

Indirect acting cholinergic drugs stimulate cholinergic receptors by inhibiting the re-uptake of ACH by inhibiting cholinesterases. Thus, indirect cholinergic drugs are also referred to as cholinesterase inhibitors or anticholinesterases.

Question 1

What is the mechanism by which Pilocarpine and Nicotine work? What is the affect of each drug?

Answer 1

Pilocarpine is a direct acting muscarinic cholinergic receptor agonist. Pilocarpine increases salivation in salivary glands where muscarinic cholinergic receptors exist.
Nicotine is a direct acting nicotinic cholinergic agonist. Nicotine excites nicotinic m cholinergic receptors in skeletal muscle causing contraction.

Question 2

How does physostigmine (esterin) increase salivation?

Answer 2

Physostigmine is a cholinesterase inhibitor (an indirect acting cholinergic drug) and thus increases synaptic levels of ACH at livary muscarinic receptors.