In response to the patient's query about how to know whether drugs are safe, the nurse explains that all medications undergo rigorous scientific testing controlled by what organization?

Choice A rationale

This choice is incorrect. Cholinergic agonists primarily affect acetylcholine receptors, not GABA receptors. GABA receptors are involved in the inhibitory neurotransmission in the central nervous system and are the target of different drug classes, such as benzodiazepines and barbiturates, which are not related to cholinergic agonists.

Choice B rationale

This choice is incorrect. Cholinergic agonists do not decrease norepinephrine activity. Norepinephrine is a neurotransmitter involved in the sympathetic nervous system response, which is different from the cholinergic system. Drugs that decrease norepinephrine activity would have a different mechanism of action, such as adrenergic antagonists.

Choice C rationale

This choice is incorrect. The primary action of cholinergic agonists is not to increase dopamine activity. Dopamine is another neurotransmitter involved in various brain functions, including reward and motor control. Cholinergic agonists specifically target acetylcholine receptors, enhancing their activity, which is not related to dopamine receptors.

Choice D rationale

This choice is correct. Cholinergic agonists increase the activity of acetylcholine receptor sites throughout the body. These drugs mimic the action of acetylcholine, a neurotransmitter that plays a key role in the parasympathetic nervous system, which regulates functions such as muscle contraction, gland secretion, and heart rate. Enhancing acetylcholine activity helps in conditions like myasthenia gravis and certain types of glaucoma.

Choice A rationale

Serotonin does not compete with anticholinergic agents at muscarinic acetylcholine receptor sites; anticholinergics target these receptors to inhibit the parasympathetic nervous system.

Choice B rationale

Anticholinergics do not increase norepinephrine at the neuromuscular junction.

Choice C rationale

Nicotinic receptors are primarily affected by different classes of drugs, such as neuromuscular blockers.

Choice D rationale

Anticholinergics inhibit the actions of the parasympathetic nervous system by blocking muscarinic receptors, reducing bodily functions like saliva production, digestion, and urination.