Effect of cholinergic agents on human spermatozoa motility

The effect of various cholinergic agents on human spermatozoa motility was studied. Both direct-acting (e.g., acetylcholine, pilocarpine) and indirect-acting (e.g., physostigmine) cholinergic agonists stimulated human spermatozoa motility. All the cholinergic antagonists (e.g., atropine, hyoscine, hexamethonium, d-tubocurarine, and succinylcholine) inhibited the spermatozoa motility. At 1 X 10(-4) M, muscarinic antagonists, atropine and hyoscine, did not influence motility, whereas nicotinic antagonists, hexamethonium, d-tubocurarine and succinylcholine, depressed motility. These observations suggest that a nicotinic-type receptor is present in spermatozoa. However, these studies did not exclude the possibility of the presence of a muscarinic receptor in spermatozoa.