Presenting Author Drexel University Philadelphia, Pennsylvania
Background Substance use disorders (SUDs) are characterized by high propensity to relapse and are highly comorbid with HIV infection. The underlying neurobiology of this relationship is poorly understood. Preclinical research on the neurobiobehavioral outcomes of progressive HIV infections may yield crucial information to improve SUD prognosis and reduce risk of relapse in people living with HIV.
Methods To model progressive HIV, adult male and female C57BL6J mice were inoculated with EcoHIV, a chimeric HIV-1 which infects murine cells by replacing envelope glycoprotein gp120 with gp80. Five weeks after inoculation mice were trained in a cocaine conditioned place preference (CPP) paradigm (10mg/kg, i.p.) followed by extinction training. Stress-induced reinstatement was assessed following administration of yohimbine, an α2 adrenergic antagonist, to determine EcoHIV effects. Neuronal activation in the prefrontal cortex (PFC) and nucleus accumbens (NAc) by cocaine exposure was assessed by quantitative analysis the expression of the immediate early gene, cFos.
Results EcoHIV and sham-inoculated mice exhibited similar cocaine CPP and extinction. However, EcoHIV mice showed significantly increased yohimbine-induced reinstatement rate (plt;0.05). cFos analysis revealed an elevated neural activation in PFC and NAc in response to cocaine. However, only neurons within infralimbic PFC (IL) and NAc shell subregions showed further increases in activity in cocaine exposed mice infected with EcoHIV vs shams.
Conclusion EcoHIV infected mice escalated stress-induced reinstatement of cocaine seeking compared to controls, suggesting that people living with HIV may be at elevated risk for stress-induced relapse. Progressive EcoHIV infection may dysregulate IL and NAcShell activity to facilitate the cocaine seeking and reinstatement. Ongoing research will characterize how EcoHIV infection dysregulate IL-NAcShell pathway specific activity during cocaine reward learning and stress-induced relapse.
