Question

Direct acting cholinergic agents mimic effect of... by doing what?

Answer 1

Direct acting cholinergic agents imitate the neurotransmitter acetylcholine (ACh), thereby increasing cholinergic activity through activation of postganglionic fibers and subsequent ACh release on target organs.

Step-by-step explanation:

Direct acting cholinergic agents mimic the effect of acetylcholine (ACh) by binding to cholinergic receptors on postganglionic nerve terminals. These agents activate postganglionic fibers, which in turn cause the release of ACh onto the target organ. The increased availability of ACh at the synaptic cleft leads to a prolonged cholinergic effect, analogous to the natural action of ACh in the parasympathetic nervous system. This is seen in various parasympathomimetic drugs that enhance cholinergic effects and in medications used to manage conditions such as nerve agent poisoning. Conversely, anticholinergic drugs such as atropine block muscarinic receptors and suppress parasympathetic activity, displaying the opposite action to direct acting cholinergic agents.

Answer 2

Direct acting cholinergic agents mimic acetylcholine by binding to cholinergic receptors and activating postganglionic fibers, which then release ACh onto the target organ, mimicking the natural parasympathetic response.

Step-by-step explanation:

Direct acting cholinergic agents mimic the effect of the neurotransmitter acetylcholine (ACh) by binding to cholinergic receptors at preganglionic synapses. This action causes the activation of postganglionic fibers, leading to the release of ACh onto the target organ. This is similar to how the body's parasympathetic nervous system operates. Parasympathomimetic drugs are a class of drugs that enhance cholinergic effects, increasing parasympathetic activity.

On the other hand, anticholinergic drugs work to suppress parasympathetic effects on organs. Atropine, for instance, acts as an antagonist to muscarinic acetylcholine receptors, efficiently blocking the overwhelming effects of excess acetylcholine as would be found in cases of nerve agent poisoning. Therefore, direct acting cholinergic agents can be understood as mimicking ACh to stimulate a response similar to natural parasympathetic activation, while anticholinergic agents block this action.