Electrical field stimulation of isolated primate sweat glands

An in vitro method is described for inducing secretion in isolated monkey eccrine sweat glands by means of electrical field stimulation (EFS). Ultrastructural analyses of these glands revealed unmyelinated nerve fibres surrounding the secretory coils. Numerous small clear vesicles, characteristic of cholinergic nerve terminals, were observed, along with a few which were large and dense-cored. EFS elicited an immediate secretory response which ceased abruptly upon termination of the current. The response was inhibited in a dose-dependent manner by atropine (IC50 1.5 X 10(-9) mol/l). Although most glands were completely inhibited by atropine, a minor atropine insensitive component was operative in some preparations. Physostigmine (10(-6) mol/l) potentiated the response to subthreshold EFS. Lidocaine (3 X 10(-4) mol/l) completely and reversibly blocked EFS but had no effect on methacholine (10(-6) mol/l) induced secretion. These results confirm that eccrine sweat gland activation is predominantly via cholinergic pathways and that EFS of isolated glands may be a useful model to study the control of secretory function in normal and diseased states.