Effects of cholinomimetic drugs on sudomotor, metabolic, respiratory, vasomotor, and temperature response in palmar hyperhidrosis

Abstract

✓ The effects of cholinomimetic drugs such as mecholyl (methacholine) and pilocarpine on autonomic functions (including sudomotor, metabolic, respiratory, vasomotor, and temperature responses) were assessed at room temperature (24°C) in three groups of individuals, including normal, hyperhidrotic, and denervated subjects. The normal group had no palmar hyerhidrosis, with intact T2–3 ganglia, the hyperhidrotic group had palmar hyperhidrosis with intact T2–3 ganglia, and the denervated group had palmar hyperhidrosis treated with T2–3 ganglionectomy. Subcutaneous administration of mecholyl and pilocarpine each produced a fall in oral temperature in the normal group. The hypothermia was brought about by a decrease in metabolic rate, an increase in local sweating rate (mainly of the upper limb and trunk), and an increase in cutaneous circulation (estimated by an increase in the upper limb and trunk skin temperatures). The autonomic functions induced by these cholinomimetic drugs were antagonized by pretreatment with atropine sulfate (an antagonist of cholinergic receptors). Moreover, the hypothermia induced by mecholyl or pilocarpine was greatly reduced in the hyperhidrotic group. The reduction in the cholinomimetic-induced hypothermia in the hyperhidrotic group was due to the reduced sudomotor and metabolic responses after the injections of these cholinomimetic drugs, as compared to those of the normal group. However, neither the excessive sweating of the palms nor the reduced cholinergic responses in the hyperhidrotic group was observed after T2–3 ganglionectomy. The data indicate that the T2–3 ganglia play a role in the elaboration or modulation of the sudomotor and metabolic responses induced by activation of certain cholinergic receptors in humans.