RESUMEN
The effects of hindlimb temperature on sciatic nerve and skeletal muscle laser Doppler vascular conductance (LDVC) were assessed in anesthetized control and streptozotocin (STZ)-diabetic rats. With core temperature at 37 degrees C and exposed hindlimb temperature at 32 degrees C, nerve LDVC was significantly lower in rats after 8 weeks of STZ diabetes than in age-matched control rats. Subsequent warming of the exposed hindlimb of control rats from 32 degrees C to 37 degrees C significantly decreased nerve LDVC by 41% and increased muscle LDVC by 48%. Because nerve LDVC was unchanged by hindlimb warming in STZ-diabetic rats, there was no significant difference between control and diabetic nerve LDVC at 37 degrees C. In a second study, after 6 weeks of STZ diabetes, changes from control nerve LDVC were shown to depend on temperature rather than the duration of surgical exposure. These findings emphasize that information about hindlimb temperature is a prerequisite for interpreting the effects of experimental diabetes on hindlimb nerve blood flow.
Asunto(s)
Temperatura Corporal/fisiología , Diabetes Mellitus Experimental/fisiopatología , Hemodinámica , Músculo Esquelético/irrigación sanguínea , Músculo Esquelético/inervación , Nervio Ciático/irrigación sanguínea , Nervio Ciático/fisiopatología , Animales , Presión Sanguínea , Femenino , Frecuencia Cardíaca , Miembro Posterior/irrigación sanguínea , Miembro Posterior/inervación , Miembro Posterior/fisiología , Flujometría por Láser-Doppler , Ratas , Ratas Sprague-Dawley , Valores de Referencia , Nervio Ciático/fisiologíaRESUMEN
The role of body and hindlimb temperature in the control of blood flow in nerve and muscle was assessed by laser Doppler flowmetry. Following surgical exposure of nerve, initial measurements were taken for 5 min at hindlimb temperatures of 30-31 degrees C. A second set of identical measurements was then made either with or without warming to 37 degrees C. Without warming, nerve laser Doppler flow (NLDF) increased by 14.5+/-3.2% (mean+/-SEM) but, with warming, decreased by 40.9+/-8.2%. In contrast, adduccamerontor magnus muscle laser Doppler flow (MLDF) decreased without warming (14.7+/-1.0%) and increased with warming (20.4+/-12.8%). Because blood pressure was not significantly altered by changes in hindlimb temperature, the patterns of changes in vascular conductance (laser Doppler flow/blood pressure) were not significantly different from that seen with NLDF and MLDF. Thus, warming to physiological temperatures was associated with decreased NLDF and vascular conductance and increased MLDF and vascular conductance. These data may have implications for the interpretation of nerve blood flow data obtained at different hindlimb temperatures.