The modulatory effect of CA1 5HT 4 receptors on memory acquisition deficit induced by harmaline

The plethora of studies indicated that there is a cross talk relationship between harmaline and serotonergic (5-HT) system on cognitive and non-cognitive behaviors. Thus, the purpose of this study is assessment the effects of CA1 5-HT4 receptor on memory acquisition deficit induced by harmaline. Harmaline was injected peritoneally, while 5-HT4 receptor agonist (RS67333) and antagonist (RS23597-190) were injected intra-CA1. For memory measurement,a single-trial step-down passive avoidance apparatus was used. The data revealed that pre-training injection of higher dose of harmaline (1 mg/kg), RS67333 (0.5 ng/mouse) and RS23597-190 (0.5 ng/mouse)decreased memory acquisitionprocess in the adult mice. Moreover, concurrent pre-training administration of subthreshold doseof RS67333 (0.005 ng/mouse) orRS23597-190 (0.005 ng/mouse)with subthreshold dose of harmaline (0.5 mg/kg, i.p.)intensify impairment of memory acquisition. All above interventions did not change locomotion and tail flick behaviors. In conclusion, the results demonstrated that the synergistic effect between both CA1 5-HT4 receptor agonist and antagonist with impairment of memory acquisition induced by harmaline, indicating a modulatory effect for CA1 5HT4 receptor on Harmaline induced amnesia.