Human sweating response to electrophoresed acetylcholine: a test of postganglionic sympathetic function.

Abstract

In recent years it has become possible to measure a number of activities of the autonomic nervous system in man, and in abnormal man attempts are made to localize the site of the lesion. When an abnormality of sympathetic activity has been shown to be due to a lesion in the efferent pathway, it is desirable to show whether the lesion is in the postganglionic fibre or more proximal. Existing tests based on the effect of injected acetylcholine have proved difficult to interpret. The present communication describes observations on the electrophoresis of acetylcholine and its effect on local sweating in normal and abnormal man. It presents evidence that electrophoresis of acetylcholine provides a reliable means of examining the function of postganglionic nerves supplying sweat glands. It is simple to perform and interpret, semi-quantitative, objective, and can localize the skin areas involved. METHODS AND MATERIALELECTROPHORESIS Acetylcholine was applied to the sweat glands by electrophoresis. The anode was a silver electroencephalography electrode enclosed in lint to give an area of 1 cm2 in contact with the skin. The cathode was much larger, a sheet of malleable metal wrapped in lint. The current, provided by three nine-volt batteries connected in series, was regulated with a 100,OOOQ variable resistance and measured on a 2mA meter. The anode was moistened with a freshly prepared 1 % solution of acetylcholine perchlorate, the cathode with tap water. To apply the drug a current of 0i125, 0-25, 0 50, 10, or 2-0 mA was passed between the electrodes for a timed period of 0-25, 0 50, 1 0, or 2-0 minutes.Thermal sweating The subject's central temperature was raised either in a hot bath (40°to 44'C), or with a radiant heat cradle over the trunk or by placing one forearm and hand in a stirred waterbath at 400 to 44°C. This was continued until there was profuse generalized sweating or the oral temperature had risen 1 'C.

Orthostatic hypotension associated with paroxysmal ventricular tachycardia.

“…The patients were warmed with a heat cradle and sweating occurred normally over face, trunk, and extremities. Iontophoresis of acetylcholine produced normal sweating and piloerection (Macmillan and Spalding, 1969). The latter tests indicate normal activity of other sympathetic nerve fibres.…”

Idiopathic orthostatic hypotension from failure of noradrenaline release in a patient with vasomotor innervation.

“…Freshly prepared O-acetylcholine perchlorate solution (10O%) was iontophoresed (Macmillan and Spalding, 1969) at several sites on the trunk, arms, and legs, and produced sweating and piloerection in areas of 1-2 cm diameter.…”

Cluster Headache: On the Significance of the Sweating Abnormality—An Editorial

“…However, although this line of reasoning seems to be relevant as far as the autonomic system in general is concerned, the sweat glands appear to be an exception to this rule. With lesions of the III sympathetic neuron, there is evidence which suggests that the sweat glands are unresponsive to chemical stimuli such as pilocarpine (21)(22)(23)(24)(25)(26)).…”