Δ9-tetrahydrocannabinol increases endogenous extracellular glutamate levels in primary cultures of rat cerebral cortex neurons: Involvement of CB1 receptors
✍ Scribed by Maria Cristina Tomasini; Luca Ferraro; Berta Wonjie Bebe; Sergio Tanganelli; Tommaso Cassano; Vincenzo Cuomo; Tiziana Antonelli
- Publisher
- John Wiley and Sons
- Year
- 2002
- Tongue
- English
- Weight
- 90 KB
- Volume
- 68
- Category
- Article
- ISSN
- 0360-4012
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✦ Synopsis
Abstract
The effects of the principal psychoactive component of marijuana, Δ^9^‐tetrahydrocannabinol (Δ^9^‐THC), on endogenous extracellular glutamate levels in primary cultures of rat cerebral cortex neurons were investigated. Locally applied Δ^9^‐THC (0.03, 3, 300, and 1,000 nM) concentration‐dependently increased basal extracellular glutamate levels (+18% ± 11%, +54% ± 10%, +90% ± 14%, +149% ± 33% vs. basal). The facilitatory effects of Δ^9^‐THC (3 and 300 nM) on cortical glutamate were fully counteracted in the presence of the selective CB~1~ receptor antagonist SR141716A (10 nM) and by replacement of the normal Krebs‐Ringer bicarbonate buffer with a low‐Ca^2+^ (0.2 mM) medium. Δ^9^‐THC application also induced an enhancement in K^+^‐evoked glutamate levels. These findings suggest that an increase in cortical glutamatergic transmission mediated by local CB~1~ receptor activation may underlie some of the psychoactive and behavioral effects of acute marijuana consumption. © 2002 Wiley‐Liss, Inc.