Ethanol ingestion in the rat induced by rewarding brain stimulation

An attempt was made to produce ethanol dependence in the rat by rewarding the ingestion of ethanol with reinforcing stimulation of the brain. Each rat was trained to lick a drinkometer tube containing an ethanol solution mixed either in water or sucrose in order to obtain rewarding electrical stimulation which was delivered through a bipolar electrode implanted stereotaxically in the lateral hypothalamus in the region of the medial forebrain bundle (MFB). During a one-hour test session, a volume of ethanol sufficient to produce pharmacological effects was reliably consumed. Following each test session, behavioral signs were noted and a blood-ethanol determination was performed. Reinforcing stimulation failed to elicit the consumption of ethanol mixed either in water or sucrose in a concentration greater than that which was above the normal preference-aversion threshold. Further, an 8-day ethanol-water preference test sequence following the last stimulation session revealed that ethanol intake did not increase significantly above that of the non-stimulated control group. These findings indicate that electrical stimulation of the lateral hypothalamus does not evoke a permanent shift in fluid preference or other signs of ethanol dependence.