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.
People with HIV often develop cognitive problems linked to disrupted fronto-striatal brain circuits, which are also affected by cannabis. HIV transgenic rats, which model HIV-associated neurocognitive disorder, showed a significant prepulse inhibition deficit compared to healthy controls, mirroring the sensorimotor gating impairment seen in people with HIV. Acute treatment with THC (1 and 3 mg/kg) reduced prepulse inhibition in control rats but not in HIV transgenic rats, indicating a relative insensitivity to THC's disruptive effects on fronto-striatal function. Cannabidiol (1, 10, and 30 mg/kg) had only minor, genotype-independent effects on prepulse inhibition. This reduced sensitivity may help explain higher cannabis use rates among people with HIV.