Alterations in the hippocampal phosphorylated CREB expression in drug state-dependent learning.

Abstract

The present study investigated the possible alterations of hippocampal CREB phosphorylation in drug state-dependent memory retrieval. One-trial step-down passive avoidance task was used to assess memory retrieval in adult male NMRI mice. Pre-training administration of ethanol (1g/kg, i.p.) induced amnesia. Pre-test administration of ethanol (1g/kg, i.p) or nicotine (0.7 mg/kg, s.c.) reversed ethanol-induced amnesia, indicating ethanol- or ethanol-nicotine induced state-dependent learning (STD). Using Western blot analysis, it was found that the p-CREB/CREB ratio in the hippocampus increased in the mice that showed successful memory retrieval as compared with untrained mice. In contrast, pre-training administration of ethanol (1g/kg, i.p.) decreased the hippocampal p-CREB/CREB ratio in comparison with the control group. The hippocampal p-CREB/CREB ratio enhanced in ethanol- and ethanol-nicotine induced STD. Moreover, memory impairment induced by pre-training administration of WIN (1 mg/kg, i.p.) improved in the animals that received pre-test administration of WIN (1 mg/kg, i.p.), ethanol (0.5 g/kg, i.p.) or nicotine (0.7 mg/kg, s.c.), suggesting a cross STD between the drugs. The p-CREB/CREB ratio in the hippocampus decreased in the of WIN-induced amnesia and STD groups in comparison with the control group. In addition, cross state-dependent learning between WIN and ethanol or nicotine was associated with the increase of the hippocampal p-CREB/CREB ratio. It can be concluded that phosphorylation of CREB in the hippocampus is a critical event underlying the interaction of co-administration of drugs on memory retrieval in passive avoidance learning.

• Authors: Sakineh Alijanpour, Ameneh Rezayof, Houri Sepehri, Ladan Delphi
• Journal: Behavioural brain research (Behav Brain Res) Vol. 292 Pg. 109-15 (Oct 01 2015) ISSN: 1872-7549 [Electronic] Netherlands
• PMID: 26055203 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2015 Elsevier B.V. All rights reserved.

Chemical References

• Benzoxazines
• Creb1 protein, mouse
• Cyclic AMP Response Element-Binding Protein
• Morpholines
• Naphthalenes
• Ethanol
• (3R)-((2,3-dihydro-5-methyl-3-((4-morpholinyl)methyl)pyrrolo-(1,2,3-de)-1,4-benzoxazin-6-yl)(1-naphthalenyl))methanone
• Nicotine

Topics

• Amnesia (chemically induced, metabolism)
• Animals
• Avoidance Learning (drug effects, physiology)
• Benzoxazines (pharmacology)
• Conditioning, Operant (drug effects)
• Cyclic AMP Response Element-Binding Protein (metabolism)
• Ethanol (pharmacology)
• Hippocampus (drug effects, metabolism)
• Male
• Memory (drug effects)
• Memory Disorders (chemically induced, metabolism)
• Mice
• Mice, Inbred Strains
• Morpholines (pharmacology)
• Naphthalenes (pharmacology)
• Nicotine (pharmacology)
• Phosphorylation (drug effects)