Methamphetamine-induced behavioral and physiological effects in adolescent and adult HIV-1 transgenic rats.

We recently reported that six consecutive days of treatment with a moderate dose of methamphetamine (METH) induced greater behavioral sensitization in adult HIV-1 transgenic (HIV-1 Tg) rats than in adult Fischer 344/NHsd (F344) non-transgenic, wild-type control animals. In the present study, we evaluated the effects of a moderate dose of METH on the brains of adolescent versus adult HIV-1 Tg male rats using both behavioral (METH-induced, stereotypic head movement) and physiological (rectal body temperature) parameters. We found that both the acute and behavior-sensitizing effects of METH were greater in HIV-1 Tg rats compared with controls and also in adolescent rats compared with adult animals, regardless of HIV-1 status. We determined that acute hyperthermic effects of METH as well as tolerance to METH-induced hyperthermia were greater in HIV-1 Tg rats than in controls. Taken together, these results suggest that both the neuroadaptations seen in HIV infection and the immaturity of the adolescent brain are associated with increased sensitivity to the psychoactive and behavior-sensitizing properties of METH. Thus, HIV-infected individuals and adolescents may be more vulnerable to the development of METH abuse and dependence than non-infected individuals and adults.