cp-94253 and Amnesia

In the present study, effects of the serotonergic system of the dorsal hippocampus (CA1) on harmaline-induced amnesia were examined. A single-trial step-down passive avoidance task was used for the assessment of memory retention in adult male NMRI mice. Pre-training intra-peritoneal (i.p.) administration of harmaline (1mg/kg) induced impairment of memory retention. Moreover, intra-CA1 administration of 5-HT1B/1D receptor agonist, CP94253 (5 ng/mouse), 5-HT1B/1D receptor antagonist, GR127935 (0.05 and 0.5 ng/mouse), 5-HT2A/2B/2C receptor agonist, α-methyl 5-HT (0.5 ng/mouse) and 5-HT2 receptor antagonist, cinancerine (0.5 ng/mouse) impaired memory acquisition, but did not affect locomotor activity and tail flick. Furthermore, pre-training intra-CA1 injection of subthreshold dose of CP94253 (0.05 ng/mouse) or GR127935 (0.005 ng/mouse) reversed impairment of memory acquisition induced by harmaline (1 mg/kg, i.p.). However, pre-training intra-CA1 infusion of subthreshold dose of α-methyl 5-HT (0.005 ng/mouse) or cinancerine (0.005 ng/mouse) with the administration of harmaline (0.5 and 1 mg/kg, i.p.) heighten impairment of memory acquisition. These findings implicate the involvement of CA1 serotonergic mechanism in harmaline-induced impairment of memory acquisition.

Topics: Amnesia; Animals; CA1 Region, Hippocampal; Central Nervous System Stimulants; Cinanserin; Harmaline; Male; Memory; Mice, Inbred Strains; Oxadiazoles; Piperazines; Pyridines; Receptor, Serotonin, 5-HT1B; Receptor, Serotonin, 5-HT1D; Receptor, Serotonin, 5-HT2A; Receptor, Serotonin, 5-HT2B; Receptor, Serotonin, 5-HT2C; Serotonin; Serotonin 5-HT1 Receptor Agonists; Serotonin 5-HT1 Receptor Antagonists