What are cholinergic side effects characterized by?

Cholinergic side effects are characterized by stimulation of the parasympathetic nervous system. This stems from the action of acetylcholine, which is the primary neurotransmitter of the parasympathetic system. When cholinergic drugs are administered or when there is an excess of acetylcholine, the effects mimic those of increased parasympathetic activity.

This results in symptoms such as increased saliva production, bronchoconstriction, decreased heart rate, increased gastrointestinal motility, and sweating. Essentially, these effects are due to enhanced stimulation of the receptors in the parasympathetic branch, leading to a 'rest and digest' state of physiological functioning. Understanding this helps in grasping how cholinergic agents can potentially impact bodily functions, particularly in therapeutic or toxicological contexts.

The other options do not accurately describe cholinergic side effects. The concept of inhibiting acetylcholine or blocking neurotransmission relates more to anticholinergic effects, which produce the opposite physiological outcomes. Decreased muscle activity does not capture the essence of cholinergic stimulation either, as increased muscle activity can also occur through different mechanisms related to cholinergic engagement.