cART Exacerbates Cocaine-Induced Cortical Neuron Hyperactivity in Non-Transgenic but Not HIV-1 Transgenic Rats

HIV-associated neurocognitive disorders (HAND) persist despite combination antiretroviral therapy (cART) and can be exacerbated by repeated cocaine (COC) exposure. Because COC, HAND, and cART independently disrupt medial prefrontal cortex (mPFC) function, their combined neurotoxic impact is a critical clinical concern. Using patch-clamp electrophysiology in HIV-1 transgenic (Tg) and non-Tg rats, we examined mPFC pyramidal neuron activity following repeated exposure to COC and/or cART. In non-Tg rats, COC and cART independently increased neuronal firing, trending toward an additive hyperactive effect when combined. Conversely, HIV-1 Tg rat neurons exhibited plateaued excitability, with no further firing elevations induced by COC or cART. Under intense depolarizing stimuli, treated neurons displayed overactivation-induced firing declines. These findings indicate that while COC and cART additively disrupt mPFC function in non-Tg rats, excitability mechanisms appear saturated in the HIV-1 Tg model. This restricted experimental context highlights the overlapping neurobiological impacts of cART and stimulant use, providing foundational insights into the comorbidity of COC use disorder and HAND.