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Long-term hippocampal interneuronopathy drives sex-dimorphic spatial memory impairment induced by prenatal THC exposure

Adán de Salas-Quiroga, Daniel García-Rincón, Daniel Gómez-Domínguez, Manuel Valero, Samuel Simón-Sánchez, Juan Paraíso‐Luna, José Aguareles, Mitona Pujadas, Carolina Muguruza, Luis Felipe Callado, Beat Lutz, Manuel Guzmán, Liset Menéndez de la Prida, Ismael Galve-Roperh

Neuropsychopharmacology January 26, 2020 DOI: 10.1038/s41386-020-0621-3 (opens in new tab)

Study at a glance

AI-extracted from the abstract
Characteristics Animal experimental study Peer reviewed
Population Mice prenatally exposed to THC, including conditional CB1R knockout mice
Intervention Δ9-tetrahydrocannabinol (THC)
Topics Cannabis
Citations 84
Key findings Prenatal THC exposure in mice caused spatial memory impairment, brain hyperexcitability, altered hippocampal oscillations, and a reduction of CCK-containing interneurons, with effects seen only in male offspring. The interneuron loss was absent when CB1 receptors were selectively removed from GABAergic interneurons, indicating a cell-autonomous THC action. The authors propose this interneuronopathy explains the sex-dimorphic cognitive deficits.

Abstract

Abstract Prenatal exposure to Δ9-tetrahydrocannabinol (THC), the most prominent active constituent of cannabis, alters neurodevelopmental plasticity with a long-term functional impact on adult offspring. Specifically, THC affects the development of pyramidal neurons and GABAergic interneurons via cannabinoid CB1 receptors (CB1R). However, the particular contribution of these two neuronal lineages to the behavioral alterations and functional deficits induced by THC is still unclear. Here, by using conditional CB1R knockout mice, we investigated the neurodevelopmental consequences of prenatal THC exposure in adulthood, as well as their potential sex differences. Adult mice that had been exposed to THC during embryonic development showed altered hippocampal oscillations, brain hyperexcitability, and spatial memory impairment. Remarkably, we found a clear sexual dimorphism in these effects, with males being selectively affected. At the neuronal level, we found a striking interneuronopathy of CCK-containing interneurons in the hippocampus, which was restricted to male progeny. This THC-induced CCK-interneuron reduction was not evident in mice lacking CB1R selectively in GABAergic interneurons, thus pointing to a cell-autonomous THC action. In vivo electrophysiological recordings of hippocampal LFPs revealed alterations in hippocampal oscillations confined to the stratum pyramidale of CA1 in male offspring. In addition, sharp-wave ripples, a major high-frequency oscillation crucial for learning and memory consolidation, were also altered, pointing to aberrant circuitries caused by persistent reduction of CCK+ basket cells. Taken together, these findings provide a mechanistic explanation for the long-term interneuronopathy responsible for the sex-dimorphic cognitive impairment induced by prenatal THC.

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