Delta-9-tetrahydrocannabinol (THC), the main psychoactive component of cannabis, reduced pain sensitivity, body temperature, and movement in HIV-1 transgenic rats and their controls, with some differences between males and females. A higher dose (3 mg/kg) also temporarily lowered motivation to work for a reward, but this effect disappeared after 16 days of daily treatment. HIV-1 transgenic rats showed lower motivation than one control strain (Fischer344) but not another (wildtype littermates), highlighting the importance of choosing appropriate control groups in research.
In a rat model of HIV, the psychoactive component of cannabis, THC, had opposite effects on different cognitive functions: it improved learning but worsened risk-based decision-making. HIV-transgenic rats and controls were tested on two tasks before and after acute and chronic THC injections. At baseline, HIV rats showed slower decision-making but intact cognition, suggesting early deficits. THC selectively altered performance in HIV rats, enhancing learning while impairing decision-making, effects not seen in controls. These findings mirror function-dependent cannabis effects observed in people with HIV and suggest THC may drive cannabis-induced cognitive changes in this population.