Sex differential effect of dexmedetomidine on fear memory extinction and anxiety behavior in adolescent rats. (December 2019)

• Record Type: Journal Article
• Authors: Jang, Minji; Jung, Taesub; Kim, Sung-Hoon; Noh, Jihyun
• Is Part Of: Neuroscience research. Volume 149(2019)
• Page Start: 29
• Page End: 37
• Publication Date: 2019-12
• Subjects: α2-Adrenergic -- Anesthesia -- Anxiolytic -- Emotional behavior -- Freezing -- Norepinephrine -- Sex; Neurosciences -- Research -- Periodicals; Neurosciences -- Research -- Japan -- Periodicals; Neurology -- Periodicals; Neurosciences -- Periodicals; Neurosciences -- Recherche -- Périodiques; Neurosciences -- Recherche -- Japon -- Périodiques; Neurosciences -- Research; Japan; Periodicals; 612.8
• DOI: 10.1016/j.neures.2019.01.006
• Languages: English
• ISSNs: 0168-0102

Abstract

Highlights: Dexmedetomidine accelerated the fear memory extinction. Dexmedetomidine reduced anxiety behavior. It was more effective in female rats than in male rats. Sex-specific effects of dexmedetomidine should be considered. Abstract: Exposure to stressful stimuli, including fear and anxiety, modulates the central noradrenergic system. Dexmedetomidine is a commonly used α2-adrenoreceptor agonist. Because the effect of fear acquisition varies between sexes, the present study was designed to investigate sex-related differences in the effects of dexmedetomidine on fear memory and anxiety-like behavior. We conducted a fear test and an elevated plus maze test in 6–8-week-old male and female rats. Two doses of dexmedetomidine (20 and 40 μg/kg) were injected intraperitoneally three times at 24 h intervals after the tests: after fear expression, extinction 1, and extinction 2. The repeated administration of dexmedetomidine showed significant acceleration of fear memory extinction in female rats but not in male rats; the effect increased proportionally to concentrations of dexmedetomidine. Compared to male rats, female rats treated with both concentrations of dexmedetomidine showed significant anxiolytic behavior after 1 week. Dexmedetomidine accelerated the fear memory extinction and reduced anxiety; it was more effective in female rats than in male rats. Our results suggest that dexmedetomidine may exert protective effects against fear-related and anxiety-like behaviors in rats with fear memory after repeated administration, and the sex-specific effects of dexmedetomidine should be considered.