Sympathetic skin responses to betel chewing.

The sympathetic skin response of habitual betel users was studied to determine the effect of betel chewing on sympathetic function. Sympathetic skin response was recorded from the hand by stimulation of the contralateral median nerve at the wrist. While the response latency remained unchanged, the response amplitude showed a progressive reduction during chewing and a gradual recovery after chewing. The present data suggest that betel chewing probably affects sympathetic function through a cholinergic action at the central generator sites.