title: Nicotine enhances the reconsolidation of novel object recognition memory in rats.
abstract: There is increasing evidence that nicotine is involved in learning and memory. However, there are only few studies that have evaluated the relationship between nicotine and memory reconsolidation. In this study, we investigated the effects of nicotine on the reconsolidation of novel object recognition memory in rats. Behavior procedure involved four training phases: habituation (Days 1 and 2), sample (Day 3), reactivation (Day 4) and test (Day 6). Rats were injected with saline or nicotine (0.1, 0.2 and 0.4 mg/kg) immediately or 6h after reactivation. The discrimination index was used to assess memory performance and calculated as the difference in time exploring on the novel and familiar objects. Results showed that nicotine administration immediately but not 6 h after reactivation significantly enhanced memory performance of rats. Further results showed that the enhancing effect of nicotine on memory performance was dependent on memory reactivation, and was not attributed to the changes of the nonspecific responses (locomotor activity and anxiety level) 48 h after nicotine administration. The results suggest that post-reactivation nicotine administration enhances the reconsolidation of novel object recognition memory. Our present finding extends previous research on the nicotinic effects on learning and memory.
authors.affiliation: Department of Physiology, College of Medicine, University of South China, Hengyang, Hunan 421001, PR China; Institute of Neuroscience, College of Medicine, University of South China, Hengyang, Hunan 421001, PR China.
authors.forename: Shaowen
authors.initials: S
authors.lastname: Tian
authors.affiliation: Department of Neurology, First Affiliated Hospital, University of South China, Hengyang, Hunan 421001, PR China.
authors.forename: Si
authors.initials: S
authors.lastname: Pan
authors.affiliation: Department of Neurology, First Affiliated Hospital, University of South China, Hengyang, Hunan 421001, PR China. Electronic address: youyong1970@126.com.
authors.forename: Yong
authors.initials: Y
authors.lastname: You
mesh_terms: D000818:Animals; D008297:Male; D008568:Memory / Q000187:drug effects*; D009538:Nicotine / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D021641:Recognition, Psychology / Q000187:drug effects*
chemical_list: D009538:Nicotine
keywords: Locomotor activity; Nicotine; Object recognition memory; Rats; Reactivation; Reconsolidation