Response of Dogs' Cutaneous Veins to Local and Central Temperature Changes

Abstract

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. SHEPHERD MICHAEL M. WEBB-PEPLOE and JOHN T.

Influence of cooling on mesenteric vascular reactivity

“…A potentiated reaction to adrenergic agents during cooling has also been reported for the dog mesenteric artery [16], whereas other studies have shown a depressed affect of noradrenaline [7]. Our experiments thus confirm the observations described previously [22,23], which showed the marked dependency of adrenergic reactions to fluctuations in temperature. The mechanism responsible for the temperature-dependent increase in sensitivity of the mesenteric artery to exogenous noradrenaline is not known from this study.…”

Hyperthermic Fibrinolysis with rt-PA: In Vitro Results

“…External application of heat appears to be unsuitable for acute occlusive arterial disease of the periphery. An external supply of heat mainly induces increased perfusion of the skin and the superficial veins with corresponding heat conduction to the surface of the extremity [21]. Therefore, an appreciable rise in temperature in the depth of the afflicted extremity cannot be expected.…”

Peripheral Mechanism Involved in Response of Dogs' Cutaneous Veins to Local Temperature Change

“…Attempts to demonstrate the afferent limb of a possible reflex arc from temperature receptors in the limb to the spinal cord and back to the vein via the sympathetic nerves led to the following conclusions (1). If temperature receptors in the limbs were involved, they had to be situated in the vein wall and not in the skin (2). The afferent fibers did not run with other sensory fibers, because cutting the appropriate dorsal spinal roots did not abolish the temperature response.…”

“…• Previous studies (1,2) have shown that the superficial limb veins of the dog constrict in response to either a decrease in central temperature or to a cooling of the blood perfusing the vein. Whereas central cooling causes constriction of the cutaneous veins in all the limbs, the constriction with local cooling is confined to the cooled limb.…”

“…Local cooling enhances the response of the smooth muscle of the vein to a given frequency of sympathetic impulses, but does not change the frequency. Central cooling '"increases" the freljueiicyT TntegTation of local and central thermal drives occurs in the vein wall (2). Local cooling stimulates temperature receptors in the limb, causing an increase in frequency of the sympathetic impulses to the veins of that limb.…”