Sex-specific effects of prenatal delta-9-tetrahydrocannabinol exposure on repetitive behavior and prefrontal cortex neuronal excitability in preadolescent rats

Abstract

Cannabis is the most common illicit drug abused worldwide, and its consumption has substantially increased among pregnant women. We previously demonstrated that male preadolescent offspring prenatally exposed to {Delta}9-tetrahydrocannabinol (THC), a model of prenatal cannabinoid exposure (PCE), exhibit a mesolimbic dopamine (DA) neuron dysfunction contributing to at-risk psychotic-like (endo)phenotypes that are unmasked by acute THC exposure at preadolescence. Dysregulation of mesocortical DA signaling along with prefrontal cortex (PFC) function is also a central feature of psychotic disorders. Furthermore, studies investigating the impact of PCE on PFC in the offspring at preadolescence, a window of heightened plasticity and vulnerability, are limited. To fill this gap, we applied a multiscale analysis of mesocortical DA transmission and PFC function in PCE preadolescent offspring by integrating behavioral, neurochemical, electrophysiological, and molecular approaches. PCE enhanced spontaneous repetitive behaviors in a male-specific manner. PCE also abolished sex differences in the intrinsic excitability of PFC pyramidal neurons and Netrin-1 expression. In addition, PCE altered the expression of genes associated with endocannabinoid signaling without changing basal and THC-induced extracellular levels of DA in the PFC. Collectively, these findings demonstrate that prenatal THC exposure disrupts both proper maturation and sexual differentiation of PFC circuitry, thus extending the impact of PCE from previously described mesolimbic abnormalities to mesocortical pathway. Finally, our data identify early cortical molecular and cellular alterations that may contribute to neuropsychiatric vulnerability later in life. Highlights* Preadolescent male rats exposed in utero to THC display repetitive behavior * Prenatal cannabinoid exposure (PCE) does not alter dopamine transmission in the PFC * PCE potentiates AMPA-mediated transmission in male pyramidal cells * PCE abolishes sex differences in Netrin-1 expression levels in the PFC