THE ROLE OF ACETYLCHOLINE IN REGULATING SECRETORY RESPONSIVENESS IN RAT SWEAT GLANDS

While retrograde regulation of neuronal development by target-derived factors in the autonomic nervous system is well established, the impor tance of anterograde influences on target development is unclear. Prev ious studies suggest that sympathetic innervation of sweat glands play s a critical role in the acquisition and maintenance of their secretor y function. To define the signal(s) responsible, we disrupted muscarin ic cholinergic transmission in developing and adult rats. Treatment of young rats with the nonselective antagonist, atropine, or an antagoni st selective for the glandular muscarinic subtype, 4-DAMP, delayed the development of secretory responsiveness. Treatment of adult animals w ith atropine caused its loss. Further, following denervation, treatmen t with the muscarinic agonist, pilocarpine, largely preserved responsi veness while untreated animals lost function. Thus, acetylcholine, who se presence in sweat gland innervation is retrogradely specified by de velopmental interactions with the target tissue, in turn plays an impo rtant role in inducing and maintaining target tissue responsiveness th rough muscarinic receptor activation. (C) 1995 Academic Press, Inc.