Do anticholinesterases have sympathetic or parasympathetic effects?

Anticholinesterases primarily have parasympathetic effects because they inhibit the enzyme that breaks down acetylcholine, leading to an accumulation of this neurotransmitter at cholinergic synapses. Acetylcholine is a key neurotransmitter in the parasympathetic nervous system, which is responsible for "rest and digest" functions. By preventing the breakdown of acetylcholine, anticholinesterases enhance the activity of the parasympathetic nervous system, resulting in effects such as increased salivation, improved gastrointestinal motility, and decreased heart rate.

Understanding the role of anticholinesterases in amplifying parasympathetic activity is critical in contexts such as treating myasthenia gravis or reversing the effects of certain types of muscle relaxants. This specific action distinguishes their effects from sympathetic responses, which are typically mediated by norepinephrine and have different physiological effects, such as increased heart rate and blood pressure.