Effect of procainization of ventromedial nucleus of hypothalamus on the feeding behavior of rats.

Abstract

Bilateral lesions in the Ventromedial nucleus of hypothalamus (VMH) cause hyperphagia and a preference for high lipid, high carbohydrate diet. Reversible lesion by procaine microinfusion produces a decrease in serum glucose and immunoreactive insulin levels. In the present study the effect of procaine microinfusion on feeding behavior and taste preference was observed. 5 h and 24 h food intake, water intake and weekly body weight of the rats was measured. Three bottle preference test was used to study the diet preferences. The 24 h food intake was found to be significantly more on 1st, 2nd and 3rd day (41 ± 6.03, 38.83 ± 6.17 and 33.66 ± 5.88 g/day, respectively) of procaine injection. There was also a significant increase in food intake at 0.25 h (4.166 ± 2.04 g) and 1 h (5 ± 0 g) as compared to saline group (0 ± 0 g at 0.25 h and 0.83 ± 2.04 g at 1 h). Post procaine water intake and body weight for seven days was not statistically significantly when compared to pre-lesion values. In the three bottles preference test, after procaine microinfusion there was a significantly increased preference for 20% sucrose and 0.15% saccharin than quinine and citric acid. The results suggest that bilateral procainization of VMH produces a transient increase in food intake and enhance preference for sweet tasting substances.