Self-administered nicotine solutions preferred to placebo by the rat.
D000818:Animals; D001522:Behavior, Animal; D002404:Catheterization; D007275:Injections, Intravenous; D007858:Learning; D008297:Male; D009538:Nicotine / Q000008:administration & dosage*; D051381:Rats; D014867:Water
D014867:Water; D009538:Nicotine