title: The serotonin 5-HT2 receptor-phospholipase C system inhibits the induction of long-term potentiation in the rat visual cortex.
abstract: The effect of serotonin 5-HT2 receptor stimulation on long-term potentiation (LTP) in the primary visual cortex was investigated by using rat brain slices in vitro. Field potentials evoked by stimulation of layer IV were recorded in layer II/III. The 5-HT2 receptor agonist 1-(2,5-dimethyl-4-iodophenyl)-2-aminopropane (DOI) did not affect baseline synaptic potentials evoked by single-pulse test stimulation, but significantly inhibited the induction of LTP in a concentration-dependent manner (0.1-10 microM). The LTP-inhibiting effect of DOI (10 microM) was blocked by the 5-HT2,7 receptor antagonist ritanserin (10 microM), but not by the 5-HT1A receptor antagonist NAN-190 (10 microM) nor by the 5-HT3,4 receptor antagonist MDL72222 (10 microM). The inhibitory effect of DOI was also blocked by the phospholipase C inhibitor U73122, but not by its inactive analogue U73343. These results suggest that visual cortex LTP is inhibited by activation of the 5-HT2 receptor-phospholipase C system. In addition, the LTP-inhibiting effect of DOI was abolished by the presence of the GABAA receptor antagonist bicuculline (10 microM), suggesting that 5-HT2 receptor-mediated inhibition of visual cortex LTP is dependent on GABAergic inhibition.
authors.affiliation: Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, The University of Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Edagawa
authors.forename: H
authors.initials: H
authors.lastname: Saito
authors.forename: K
authors.initials: K
authors.lastname: Abe
mesh_terms: D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology; D000662:Amphetamines / Q000494:pharmacology; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D004594:Electrophysiology; D004963:Estrenes / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology*; D008297:Male; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology; D011760:Pyrrolidinones / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000378:metabolism; D011985:Receptors, Serotonin / Q000378:metabolism*; D016713:Ritanserin / Q000494:pharmacology; D012702:Serotonin Antagonists / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D014326:Tropanes / Q000494:pharmacology; D010738:Type C Phospholipases / Q000378:metabolism*; D014793:Visual Cortex / Q000737:chemistry* / Q000201:enzymology*; D005680:gamma-Aminobutyric Acid / Q000502:physiology
chemical_list: D000662:Amphetamines; D004963:Estrenes; D018756:GABA Antagonists; D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011760:Pyrrolidinones; D011963:Receptors, GABA-A; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; D014326:Tropanes; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; C058895:1-(2-methoxyphenyl)-4-(4-(2-phthalimido)butyl)piperazine; C074854:U 73343; D016713:Ritanserin; D005680:gamma-Aminobutyric Acid; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D010738:Type C Phospholipases; C042253:bemesetron; C015952:4-iodo-2,5-dimethoxyphenylisopropylamine; D001640:Bicuculline