Physostigmine has effects at which of the following synapses?

Physostigmine is a reversible acetylcholinesterase inhibitor that enhances the effects of acetylcholine by preventing its breakdown. This means that it can impact any synapse where acetylcholine is a neurotransmitter.

In the context of the autonomic nervous system (ANS), physostigmine increases the level of acetylcholine at both the sympathetic and parasympathetic branches, leading to amplified cholinergic responses, such as slowed heart rate and increased glandular secretions.

At the neuromuscular junction (NMJ), it act similarly by prolonging the action of acetylcholine, which facilitates muscle contraction by enhancing communication between motor neurons and skeletal muscles. This is particularly relevant in conditions like myasthenia gravis, where neuromuscular transmission is impaired.

Additionally, physostigmine penetrates the blood-brain barrier, which enables it to exert effects within the central nervous system (CNS). This capability allows it to be utilized in the treatment of conditions affecting cognitive function, such as Alzheimer's disease, by increasing cholinergic activity in the brain.

Thus, the correct choice reflects physostigmine's ability to affect various types of synapses, including those in the ANS, neurom