Pickel VM, Bourie F, Chan J, Mackie K, Lane DA, Wang G. Chronic adolescent exposure to ∆9-tetrahydrocannabinol decreases NMDA current and extrasynaptic plasmalemmal density of NMDA GluN1 subunits in the prelimbic cortex of adult male mice.
Neuropsychopharmacology 2020;
45:374-383. [PMID:
31323660 PMCID:
PMC6901492 DOI:
10.1038/s41386-019-0466-9]
[Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 07/01/2019] [Accepted: 07/12/2019] [Indexed: 12/21/2022]
Abstract
Adolescence is a vulnerable period of development when limbic connection of the prefrontal cortex (PFC) involved in emotional processing may be rendered dysfunctional by chronic exposure to delta-9-tetrahydrocannabinol (∆9-THC), the major psychoactive compound in marijuana. Cannabinoid-1 receptors (CB1Rs) largely mediate the central neural effects of ∆9-THC and endocannabinoids that regulate NMDA receptor-dependent synaptic plasticity of glutamatergic synapses in the prelimbic prefrontal cortex (PL-PFC). Thus, chronic occupancy of CB1Rs by ∆9-THC during adolescence may competitively decrease the functional expression and activity of NMDA receptors in the mature PL-PFC. We used a multidisciplinary approach to test this hypothesis in adult C57BL/6J male mice that received vehicle or ∆9-THC in escalating doses (2.5-10 mg/kg/ip) through adolescence (postnatal day 29-43). In comparison with vehicle, the mice receiving ∆9-THC showed a hyperpolarized resting membrane potential, decreased spontaneous firing rate, increased current-induced firing threshold, and decreased depolarizing response to NMDA in deep-layer PL-PFC neurons analyzed by current-clamp recordings. Electron microscopic immunolabeling in the PL-PFC of adult mice that had received Δ9-THC only during adolescence showed a significant (1) decrease in the extrasynaptic plasmalemmal density of obligatory GluN1-NMDA subunits in dendrites of all sizes and (2) a shift from cytoplasmic to plasmalemmal distribution of GluN1 in large dendrites receiving mainly inhibitory-type synapses from CB1R-labeled terminals. From these results and concomitant behavioral studies, we conclude that social dysfunctions resulting from excessive intake of ∆9-THC in the increasingly available marijuana products used by male teens may largely reflect circuit defects in PL-PFC networks communicating through endocannabinoid-regulated NMDA receptors.
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