Regulation and Characteristics of Cold-Induced Vasodilation,

Abstract : The regulation and patterns of cold-induced vasodilation (CIVD) were identified by simultaneously monitoring circulatory and thermal responses during local cold exposure of a hindlimb in 22 cats anesthetized with chloralose. The different patterns of CIVD were categorized as hunting, sustained, combination of hunting and sustained, or no CIVD. The different regulatory mechanisms mediating CIVD were classified as baroreceptor mediated, active vasodilation, or redistribution of blood flow to skin. These cold unacclimatized cats produced primarily a hunting pattern of CIVD which was regulated predominantly by baroreceptor reflexes. The proposed mechanism of this CIVD response involves a sequence of neural reflexes elicited by cold pain, cold pressor response, baroreceptor reflex, and CIVD providing feedback inhibition of cold nociception. Differences in the pattern and regulation of CIVD may be related to the level of cold adaptation, and may influence the effectiveness of peripheral cryoprotection provided by CIVD.