Ganglionic stimulants like nicotine can activate nicotinic receptors in autonomic ganglia, resulting in the stimulation of both sympathetic and parasympathetic responses. Although they have limited medical use, nicotine has been used experimentally to help identify nerve fibers. Ganglionic blockers are competitive antagonists at nicotinic receptors that reduce autonomic tone, and were once used to treat hypertension and peptic ulcers but caused intolerable side effects. Trimethaphan is a short-acting ganglionic blocker occasionally used for controlled hypotension. Mecamylamine has been studied for smoking cessation by blocking nicotine's rewarding effects but also causes constipation. Currently there is no significant