The ameliorating effects of NMDA receptor agonists on histamine H1 antagonist-induced memory and hippocampal theta disruptions are prevented by the H3 receptor agonist in rats.
In the present study, we investigated the effect of imetit, a selective histamine H(3) agonist, on the improvement of NMDA receptor agonists in H(1) antagonist-induced working memory deficit and the decrease of hippocampal theta activity in rats. Pyrilamine (35 mg/kg, i.p.) impaired spatial memory and decreased hippocampal theta activity during the radial maze task. In addition, intrahippocampal injection of D-cycloserine (1 microg/side) and spermidine (10 microg/side) improved the pyrilamine-induced working memory deficit and the decrease of hippocampal theta activity. The improvement effects of D-cycloserine and spermidine were antagonized by intrahippocampal injection of imetit (10 microg/side). These results indicate that, the facilitation of neurotransmitter release from the presynaptic terminals besides direct stimulation of postsynaptic NMDA receptors take part in the improvements of NMDA receptor agonists on pyrilamine-induced spatial memory deficit and the decrease of hippocampal theta activity.
Masuoka
Takayoshi
T
Department of Medicinal Pharmacology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8530, Japan.
Kamei
Chiaki
C
D000818:Animals; D003523:Cycloserine / Q000494:pharmacology; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects*; D017442:Histamine Agonists / Q000494:pharmacology*; D006634:Histamine H1 Antagonists; D007093:Imidazoles / Q000494:pharmacology*; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D008568:Memory / Q000187:drug effects; D008569:Memory Disorders / Q000139:chemically induced / Q000188:drug therapy*; D011738:Pyrilamine; D011897:Random Allocation; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000819:agonists*; D013028:Space Perception / Q000187:drug effects; D013095:Spermidine / Q000494:pharmacology; D013826:Theta Rhythm / Q000187:drug effects*; D013890:Thiourea / Q000031:analogs & derivatives* / Q000494:pharmacology
D018690:Excitatory Amino Acid Agonists; D017442:Histamine Agonists; D006634:Histamine H1 Antagonists; D007093:Imidazoles; D016194:Receptors, N-Methyl-D-Aspartate; C077430:imetit; D003523:Cycloserine; D013890:Thiourea; D011738:Pyrilamine; D013095:Spermidine