title: Deletion of CB2 cannabinoid receptors reduces synaptic transmission and long-term potentiation in the mouse hippocampus.
abstract: The effects of cannabinoids are mostly mediated by two types of cannabinoid receptors--CB1 receptors in the nervous system and CB2 receptors in the immune system. However, CB2 cannabinoid receptors have recently been discovered in the brain and also implicated in neurophysiological functions. The deletion of CB2 receptors in mice induces long-term memory deficits and schizophrenia-like behaviors, implying that endogenous activity of CB2 receptors might be involved in neuropsychiatric effects. Little is known about the cellular mechanisms by which physiological activation of CB2 receptors modulates neuronal functions. We aimed to determine how deletion of CB2 receptors in mice affects synaptic transmission and plasticity. Electrophysiological and morphological studies indicated that CB2 receptor knockout resulted in decreases in excitatory synaptic transmission, long-term potentiation, and dendritic spine density in the hippocampus. Our data imply that endogenous activity of CB2 receptors might contribute to the maintenance of synaptic functions and the expression of normal long-term potentiation. This study provides insights into the role of CB2 cannabinoid receptors in regulating cognitive functions such as long-term memory.
authors.affiliation: Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, 30912.
authors.forename: Yong
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, 30912.|Department of Neurology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, 30912.
authors.forename: Jimok
authors.initials: J
authors.lastname: Kim
mesh_terms: D015763:2-Amino-5-phosphonovalerate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001892:Camphanes / Q000494:pharmacology; D004558:Electric Stimulation; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006624:Hippocampus / Q000166:cytology*; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000187:drug effects / Q000235:genetics*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018613:Microscopy, Confocal; D018408:Patch-Clamp Techniques; D011720:Pyrazoles / Q000494:pharmacology; D043885:Receptor, Cannabinoid, CB2 / Q000037:antagonists & inhibitors / Q000172:deficiency* / Q000235:genetics
chemical_list: D001892:Camphanes; D018691:Excitatory Amino Acid Antagonists; D011720:Pyrazoles; D043885:Receptor, Cannabinoid, CB2; C110630:SR 144528; C064539:2-amino-4-methyl-5-phosphono-3-pentenoic acid; D049452:Green Fluorescent Proteins; D015763:2-Amino-5-phosphonovalerate
keywords: confocal imaging; dendritic spine; electrophysiology; knockout mouse; memory