Temperature induced peripheral blood flow changes in lizards

Summary The influence of local temperature changes within the posterior portion of the body on dorsal aorta blood flow (), femoral arterial pressure (P_a), peripheral resistance (R), skin blood flow () and skeletal muscle blood flow () was examined in unanesthetized lizards (Iguana iguana andTubinambis nigropunctatus). In response to local heating of the hind legs and tail and increased,P_a was generally unchanged,R decreased and decreased or was unchanged (Fig. 2). It is suggested that the acquisition of heat may be favored by diverting the increase in away from the muscle to the warmer skin. In response to cooling and decreased,P_a was generally unchanged, R increased and increased or was unchanged. Hence, during cooling the retention of heat may be favored by diverting blood away from the skin to the deeper muscle. The muscle-skin shunt is under sympathetic control since following blockade with phenoxybenzamine HCL (Dibenzyline) muscle blood flow changes in response to temperature were qualitatively similar to those of skin (Fig. 4). These changes in peripheral circulatory patterns are independent of changes in heart rate or deep body temperature.Baker and Weathers were predoctoral and postdoctoral trainees, respectively, under USPHS Grant HE-05696. This study was also supported by NSF Grant GB-8523 and Los Angeles County Heart Association Grant 437IG.