title: Blockade of GPR55 in the dorsolateral striatum impairs performance of rats in a T-maze paradigm.
abstract: To investigate the role of GPR55 receptors, which are expressed in human and rat striatum (a structure that regulates procedural memory), Wistar rats received five training sessions (10 trials/session, 1 session/day) to solve a T-maze paradigm. From these data, we constructed learning curves following pharmacological manipulation of GPR55. Five minutes before each session, animals received bilateral intradorsolateral striatum injections of noladin-ether (3.1 nmol/l; endogenous agonist of GPR55 and CB1 receptors), CID16020036 (5.6 nmol/l; GPR55 antagonist), AM251 (5.6 nmol/l; CB1 antagonist), or a combination of noladin-ether with each antagonist. Noladin-ether by itself induced no significant changes in the learning curve. Nevertheless, while simultaneously blocking CB1 receptors (with AM251), noladin-ether improved acquisition. In contrast, while simultaneously blocking GPR55 (with CID16020036), noladin-ether weakened acquisition. CID16020036 by itself impaired learning, whereas AM251 by itself reduced the efficiency in the task. There were no differences between groups in the latency to reach the arms from the starting point; thus, no motor coordination impairments interfered with this task. These results strongly suggest a role of GPR55 in procedural memory and constitute the first evidence indicating that this receptor regulates cognitive processes.
authors: aLaboratory of Cannabinoids, Department of Physiology bLaboratory of Cognitive Neurogenomics, Coordination of Psychophysiology, School of Psychology, National Autonomus University of Mexico, D.F., Mexico.
authors: Bruno A
authors: BA
authors: Marichal-Cancino
authors: Asai
authors: A
authors: Sánchez-Fuentes
authors: Mónica
authors: M
authors: Méndez-Díaz
authors: Alejandra E
authors: AE
authors: Ruiz-Contreras
authors: Oscar
authors: O
authors: Prospéro-García
mesh_terms: D000818:Animals; D053961:Azabicyclo Compounds / Q000494:pharmacology; D001565:Benzoates / Q000494:pharmacology; D003071:Cognition / Q000502:physiology; D003342:Corpus Striatum; D005989:Glycerides / Q000494:pharmacology*; D008297:Male; D018782:Maze Learning / Q000187:drug effects*; D008568:Memory / Q000187:drug effects*; D010880:Piperidines / Q000494:pharmacology; D011720:Pyrazoles / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D043882:Receptors, Cannabinoid / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: C583126:4-(4-(3-hydroxyphenyl)-3-(4-methylphenyl)-6-oxo-1H,4H,5H,6H-pyrrolo(3,4-c)pyrazol-5-yl)benzoic acid; D053961:Azabicyclo Compounds; D001565:Benzoates; C568825:GPR55 protein, rat; D005989:Glycerides; D010880:Piperidines; D011720:Pyrazoles; D043882:Receptors, Cannabinoid; D043562:Receptors, G-Protein-Coupled; C424442:noladin ether; C103505:AM 251