Abstract
DÖRING, H., H. SANN AND I. SCHMIDT. Development of vasomotor control in lean (+/?) and genetically obese (fa/fa) rat pups. PHYSIOL BEHAV 66(2) 303–308, 1999.—Using laser Doppler flowmetry, we determined whether vasomotor control is already functional in 7-, 11-, and 16-day-old rat pups, and whether differences in vasomotor responses between 16-day-old lean (+/?) and fatty ( fa/fa) pups occur. For 3 h, at the end of their daily light phase, the pups were exposed to 30-min step changes of ambient temperature ( T a) alternating between thermoneutrality and cold loads resulting in a 50–100% increase of metabolic rate (MR) above its thermoneutral value, while core temperature ( T c), skin blood flux at the hindpaw, and MR were recorded. In all age groups, blood flux changed significantly in response to these T a changes. The time needed for a significant change in blood flux was shorter in the 7-day-old than in the 16-day-old lean pups, while the T a dependency of T c was more pronounced in the younger pups. Comparison of the responses of the 16-day-old fatty and lean pups showed a parallel shift to lower values in the correlation of T a with MR in the fa/fa pups, but no difference in the correlation of T a with blood flux. This demonstrates that the vasomotor control system in the rat is already functional by the age of 7 days, and that the fa/fa lesion influences the vasomotor control less than the metabolic cold defense.
Published Version
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