Response of dogs' cutaneous veins to local and central temperature changes.

To study the separate actions of peripheral and central temperaturesensitive systems on the cutaneous veins of the dog, a cross-circulation preparation was made in which hindleg and central temperatures could be varied independently. The lateral saphenous vein of a vascularly isolated hindleg was cross-perfused at constant flow; the difference between perfusion and femoral vein pressures was a measure of venomotor activity. With central temperature constant, local cooling of one leg from 47° to 17°C caused the lateral saphenous vein to constrict; sensitivity to cooling was maximal between 42° and 27°C. With leg temperature constant, central cooling caused the lateral saphenous vein to constrict; over the range of 40° to 33°C, the constriction was linearly related to the decrease in temperature. Central heating reduced the response to local cooling, whereas central cooling had the opposite effect. Thus a decrease in central temperature from 38° to 34°C increased the venoconstrictor response to local cooling from 42° to 22°C by a factor of ten or more. ADDITIONAL