Cutaneo-Visceral Vasomotor Reflexes in the Cat

The use of localized cutaneous stimulation in the treatment of visceral and other deeply located lesions has been based mainly on empirical considerations. Certain investigators, particularly Boas 1 and Freude and Ruhmann, 2 advanced data which support the assumption that localized cutaneous stimulation by means of warm applications results in vasodilatation in the corresponding segments of the gastro-intestinal tract. Certain data also support the assumption that localized cooling of the skin results in vasoconstriction in the viscera in the corresponding segments. There is no general agreement regarding the vascular reactions in the viscera elicited by localized cutaneous stimulation or the mechanisms through which such reactions are brought about.

The present series of experiments has been carried out to determine more accurately than has been indicated by previous studies whether appreciable circulatory changes in visceral organs can be brought about by loocalized cutaneous stimulation and whether the changes which occur represent direct effects of the stimulation employed or reflex phenomena.

Decerebrate preparations of the cat have been used in order to avoid the vitiating effects of anesthesia. The stimulating agents employed have been warm and cold applications and vacuum cups applied to the skin of the back and lateral surfaces of the trunk from which the hair had been removed. The circulatory changes brought about in the stomach and intestine were observed with the viscus exposed through a midventral incision, and recorded by means of photography and plethysmograph records.

Moderate cooling of the skin of the back or lateral surface by means of cold applications from the fifth or sixth thoracic segment caudalward consistently resulted in vasoconstriction in the stomach and intestine. Moderate warming of the skin in the same areas by means of warm applications at approximately 45°C consistently resulted in vasodilatation in the stomach and intestine.