title: Striatal GABAergic and cortical glutamatergic neurons mediate contrasting effects of cannabinoids on cortical network synchrony.
abstract: Activation of type 1 cannabinoid receptors (CB1R) decreases GABA and glutamate release in cortical and subcortical regions, with complex outcomes on cortical network activity. To date there have been few attempts to disentangle the region- and cell-specific mechanisms underlying the effects of cannabinoids on cortical network activity in vivo. Here we addressed this issue by combining in vivo electrophysiological recordings with local and systemic pharmacological manipulations in conditional mutant mice lacking CB1R expression in different neuronal populations. First we report that cannabinoids induce hypersynchronous thalamocortical oscillations while decreasing the amplitude of faster cortical oscillations. Then we demonstrate that CB1R at striatonigral synapses (basal ganglia direct pathway) mediate the thalamocortical hypersynchrony, whereas activation of CB1R expressed in cortical glutamatergic neurons decreases cortical synchrony. Finally we show that activation of CB1 expressed in cortical glutamatergic neurons limits the cannabinoid-induced thalamocortical hypersynchrony. By reporting that CB1R activations in cortical and subcortical regions have contrasting effects on cortical synchrony, our study bridges the gap between cellular and in vivo network effects of cannabinoids. Incidentally, the thalamocortical hypersynchrony we report suggests a potential mechanism to explain the sensory "high" experienced during recreational consumption of marijuana.
authors.affiliation: Department of Systems Neuroscience,  Institut d'Investigacions Biomèdiques August Pi i Sunyer, 08016 Barcelona,  Spain.
authors.forename: Carola
authors.initials: C
authors.lastname: Sales-Carbonell
authors.forename: Pavel E
authors.initials: PE
authors.lastname: Rueda-Orozco
authors.forename: Edgar
authors.initials: E
authors.lastname: Soria-Gómez
authors.forename: György
authors.initials: G
authors.lastname: Buzsáki
authors.forename: Giovanni
authors.initials: G
authors.lastname: Marsicano
authors.forename: David
authors.initials: D
authors.lastname: Robbe
mesh_terms: D000818:Animals; D002186:Cannabinoids / Q000494:pharmacology*; D002540:Cerebral Cortex / Q000166:cytology* / Q000502:physiology; D003342:Corpus Striatum / Q000166:cytology* / Q000502:physiology; D003344:Cortical Synchronization; D003511:Cyclohexanols; D004576:Electromyography; D059330:GABAergic Neurons / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism; D051379:Mice; D008817:Mice, Mutant Strains; D009415:Nerve Net / Q000187:drug effects / Q000502:physiology*; D010880:Piperidines; D011720:Pyrazoles; D043884:Receptor, Cannabinoid, CB1 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D018709:Statistics, Nonparametric; D013378:Substantia Nigra / Q000502:physiology; D013788:Thalamus / Q000502:physiology
chemical_list: D002186:Cannabinoids; C543264:Cnr1 protein, rat; D003511:Cyclohexanols; D010880:Piperidines; D011720:Pyrazoles; D043884:Receptor, Cannabinoid, CB1; C103505:AM 251; D018698:Glutamic Acid; C054649:3-(2-hydroxy-4-(1,1-dimethylheptyl)phenyl)-4-(3-hydroxypropyl)cyclohexanol