ACUTE AND CHRONIC NICOTINE EFFECTS ON MULTIPLE-SCHEDULE BEHAVIOR - ORAL AND SE ROUTES

For rats responding on a 3 h FI 4 min FR 20 schedule of food reinforce ment, presession SC nicotine doses (0.1-0.8 mg/kg) produced depression in all responding followed by stimulation of FI responding that was d ependent upon both time and dose. With daily presession 0.8 mg/kg SC n icotine injections for 9 days, no tolerance to the depressive or stimu latory effects of nicotine occurred. When nicotine solutions were oral ly self-administered by presession exposure to 3 h of schedule-induced polydipsia, the subsequent FR responding was unaffected, but the degr ee of FI response stimulation and its duration occurred in a dose-rela ted fashion (1.18-4.10 mg/kg). Prolonged daily sessions of oral nicoti ne self-administration provide a technique for investigating the effec ts of chronic exposure to nicotine. The postingestive effects of nicot ine reveal stimulatory effects that last for at least 3 h.