SUCROSE RICH DIET MODIFIES THERMOGENIC RESPONSE TO INJECTION OF MUSCIMOL INTO THE POSTERIOR HYPOTHALAMUS IN THE RAT

The firing rate of the nerves innervating interscapular brown adipose tissue, temperatures of colon and interscapular brown adipose tissue, heart rate and oxygen consumption were monitored in urethane-anaesthet ized male Sprague-Dawley rats fed with a sucrose rich diet. These vari ables were measured for 40 min before (baseline values) and 40 min aft er a 56 ng muscimol injection into the posterior hypothalamus. The sam e variables were monitored in other rats fed with a laboratory standar d diet. Saline was injected into the posterior hypothalamus of control rats fed with sucrose or standard diet. Muscimol injection induced a decrease in firing rate, interscapular brown adipose tissue and coloni c temperatures and oxygen consumption. This reduction was more evident in the rat fed with a sucrose rich die? than animals fed with standar d diet. The kind of diet did not modify the decrease in heart rate ind uced by muscimol. These findings suggest that a sucrose rich diet modi fies GABA-ergic responses to muscimol injection into the posterior hyp othalamus.