Sensibilidade comportamental cruzada entre anfetamina e nicotina induzida na adolescência persiste até a idade adulta.

Abstract

Behavioral sensitization is a progressive and enduring enhancement of the motor stimulant effects of psychostimulants and other drugs of abuse, elicited by repeated administration of these drugs. This phenomenon has been extensively studied in experimental animals and has been implicated as a key component in drug addiction. Nicotine and psychostimulants are often abused in combination. The aim of the present study was to examine the cross-sensitization between nicotine and amphetamine in rats exposed to repeated treatment with the drugs during adolescence. We evaluated the effects of the treatment with nicotine (0.4 mg/kg; s.c.) or amphetamine (5.0 mg/kg, i.p.) from postnatal day (P) 28 P34 on amphetamine- (1.0, 2.5, 5.0 mg/kg, i.p.) or nicotine induced locomotor activity 3 (P37) or 10 days (P44) after drug treatment ended. Further, the effects of amphetamine or nicotine were examined 36 days (P70) after nicotine or amphetamine treatments to determine whether the effects of drug exposure during periadolescence persisted into adulthood. Adolescent animals pretreated with amphetamine were sensitized to the locomotor-activating effects of nicotine. Moreover, the pretreatment with nicotine during adolescence increased locomotor activity induced by 5.0 mg/kg of amphetamine. Although adult rats are less sensitive to nicotine, this drug significantly increased the locomotor activity in adult rats that were pretreated with amphetamine during adolescence. In addition, in adult rats, the pretreatment with nicotine during adolescence increased locomotor activity induced by 1.0 mg/kg of amphetamine. These data suggest the crossensitization between amphetamine and nicotine in adolescent rats. Moreover, the sensitization is long-lasting and persists until adulthood.