Abolishment of fear memory-disruptive effects REM sleep deprivation by harmane

Abstract

Harmane, as a neuromodulator, implicates in the learning and memory processes. However, rapid eye movement (REM) sleep deprivation negatively affects these processes. Here, we investigated the effects of harmane (2.5 mg/kg) on the regulation of fear memory in free moving groups (FMG), large platform groups (LPG) and REM-deprived mice. We employed a flower pot technique for REM sleep deprivation and a Pavlovian fear conditioning paradigm for assessment of fear memories. FMGs received two or three pre-training intraperitoneal administrations of harmane at 12 h intervals, impaired contextual memory retention but those received three harmane administrations showed an auditory memory disruption. LPGs, with or without harmane, did not alter fear memories compared to their respective FMGs, indicating the inability of stress on fear responses of FMGs. Moreover, 12, 24 and 36 h REM sleep deprivation impaired contextual memory retrieval, while 24 and 36 h REM sleep deprivation impaired auditory fear memory retention. Furthermore, harmane only abolished contextual and auditory fear memory deficits induced by 24 h REM sleep deprivation. The data suggests a modulatory role for harmane in REM sleep deprivation response on fear memory.