Eliciting conditioned taste aversion by cobra venom neurotoxin in rats.

An attempt is made to study conditioned taste aversion (CTA) using cobra venom antivenom or lithium chloride as the Unconditioned Stimulus (US). Twenty-four hour water deprived rats were habituated for two consecutive days to drinking tap water in the drinking box for 15 minutes daily. On 3rd day they were allowed to drink 0.1% sodium saccharin. Thirty minutes later, they were injected with cobra venom (45 micrograms), antivenom (0.022 microliter), antivenom followed by venom, lithium chloride (0.15 M, 4% body weight) or physiological saline. After two days of recovery the animals were water deprived for twenty four hours and water intake was measured on the 7th and 8th day. Retention test on the 9th day shows reduced saccharin consumption in the lithium chloride and venom groups. CTA was significantly reduced in the antivenom-venom group and absent in the antivenom and control group. It is concluded cobra venom can induce clear-cut CTA in rats.