Behavioural sensitization to nicotine precedes the onset of nicotine-conditioned locomotor stimulation

Context-dependent behavioural sensitization to nicotine develops faster and is more robust than context-independent sensitization. However, some findings suggest that behavioural sensitization develops irrespective of context. In this study an attempt was made to dissociate the development of context-dependent nicotine sensitization from the onset of nicotine-conditioned locomotor stimulation. Seven days of daily nicotine administration (0.6 mg/kg, s.c.) paired with exposure to locomotor activity boxes produced stable and consistent behavioural sensitization, at which time no nicotine-induced conditioned locomotor stimulation could be demonstrated. However, after an additional two days of nicotine treatment, i.e. on day 9, nicotine-conditioned behavioural stimulation was observed. Our findings suggest that behavioural sensitization to nicotine appears to reach a plateau before induction of nicotine-conditioned locomotor stimulation.