A behavioral and biochemical comparison of 2 different sensitization protocols: chronic vs two injection protocols (TIPS)

MLEWSKI, E. C.; BELTRAN-GONZALEZ, J; ARIAS, C.; PAGLINI, M.G.; GIRAULT, J.A.

Huerta-Grande

Congreso; Sociedad Argentina de Neurociencias; 2010

Locomotor sensitization to psichostimulants depends on the temporal pattern of drug exposure. Studies show that a single exposure to psychostimulants induces behavioral sensitization. The goal of this study was to compare the behavioral response of 2 different sensitization protocols, chronic and two injection protocol (TIP). Adult mice were divided in 2 groups (chronic or TIP). Subjects from the chronic condition received 5 injection of cocaine (coc, 20mg/kg) or vehicle and those from TIP receive only one injection. Fourteen days after the first inyection the subjects from each condition received a challenge of coc or vehicle. Both protocols produced locomotor sensitization. The temporal pattern induced by the chronic was significantly different than the one induced by the TIP. The maximun response in the chronic group was reached earlier. Twenty min after injection locomotor activity in the chronic group was significantly lower than in the TIP, and by the end of the test, the chronic group showed again significantly higher activity scores. The diferences observed in the temporal pattern of the slope of the 2 protocols seems to be asociated with biochemical changes induced by the differential exposure to the drug rather than differences in exposure to the testing environment.