Preference and aversion for brain stimulations estimated by the conditioned place preference.

Rats implanted with chronic electrode into the medial forebrain bundle at the level of the hypothalamus (which elicited self-stimulation behaviour) display conditioned place preference after repeated stimulations of this area; conversely rats implanted into the mesencephalic dorso-medial tegmentum (which elicited switch-off behaviour) present conditioned place aversion after such repeated stimulations. Furthermore rats implanted in these two area without exhibiting self-stimulation or switch-off behaviours also display preference or aversion for the location paired with the brain stimulations. It was thus hypothesized that the conditioned place preference procedure seemed to present a higher sensitivity than the bar pressing procedures to detect preference or aversion for brain stimulation. Moreover the activation of the medial forebrain bundle which was associated with positive affect is more effective for a long term retention of the preferred location than midbrain periventricular reticular activation which induces a negative affect

Differential-effects of Cerulein and Bombesin On the Ethanol Intake in the Rat

Male Wistar rats were allowed to drink either water or water mixed with ethyl alcohol (4%, 8% and 12%) as part of a water-deprived procedure. The decapeptide caerulein (1,3 and 6-mu-g/kg i.p.), a cholecystokinin analog, decreased the intake of ethanol while the consumption of tap water remained unchanged in a choice paradigm. The addition of quinine (a bitter substance) in drinking bottles did not significantly modify the fluid consumption while the i.p. injection of caerulein produced a significant decrease in the consumption of the saccharin containing bottle. The i.p. administration of bombesin (10 and 20-mu-g/kg) failed to modify the intake of water or ethanol solution in water-deprived animals. Interpretations are given in terms of the action of the cholecystokinin analog on differences in the taste intensity induced by the beverage or in terms of a direct consequence of the caerulein-induced decreased gastric emptying effect leading to an accumulation of ethanol in the gut