Central effect of epinephrine and norepinephrine on the palmar sweat index

¹ Department of Anatomy, Royal Free Hospital School of Medicine, London, W.C. 1, England

An investigation is reported into the effect and site of action of systemically administered epinephrine and norepinephrine on numbers of active sweat glands in an area 4 mm sq over the central whorl of a middle finger pad (palmar sweat index). Both epinephrine and norepinephrine depressed the index. Although 20 mg phenoxybenzamine, an adrenergic blocking agent, had no effect itself on the index, it prevented the decrease which follows administration of epinephrine; this was probably due to a central effect, as experiments designed to eliminate local effects of the hormones on either the sweat glands themselves or their blood supply suggested that depression of the index was mediated through central nervous mechanisms.