title: Basolateral amygdala GABA-A receptors mediate stress-induced memory retrieval impairment in rats.
abstract: The present study was designed to investigate the involvement of GABA-A receptors of the basolateral amygdala (BLA) in the impairing effect of acute stress on memory retrieval. The BLAs of adult male Wistar rats were bilaterally cannulated and memory retrieval was measured in a step-through type passive avoidance apparatus. Acute stress was evoked by placing the animals on an elevated platform for 10, 20 and 30 min. The results indicated that exposure to 20 and 30 min stress, but not 10 min, before memory retrieval testing (pre-test exposure to stress) decreased the step-through latency, indicating stress-induced memory retrieval impairment. Intra-BLA microinjection of a GABA-A receptor agonist, muscimol (0.005-0.02 μg/rat), 5 min before exposure to an ineffective stress (10 min exposure to stress) induced memory retrieval impairment. It is important to note that pre-test intra-BLA microinjection of the same doses of muscimol had no effect on memory retrieval in the rats unexposed to 10 min stress. The blockade of GABA-A receptors of the BLA by injecting an antagonist, bicuculline (0.4-0.5 μg/rat), 5 min before 20 min exposure to stress, prevented stress-induced memory retrieval. Pre-test intra-BLA microinjection of the same doses of bicuculline (0.4-0.5 μg/rat) in rats unexposed to 20 min stress had no effect on memory retrieval. In addition, pre-treatment with bicuculline (0.1-0.4 μg/rat, intra-BLA) reversed muscimol (0.02 μg/rat, intra-BLA)-induced potentiation on the effect of stress in passive avoidance learning. It can be concluded that pre-test exposure to stress can induce memory retrieval impairment and the BLA GABA-A receptors may be involved in stress-induced memory retrieval impairment.
authors.affiliation: Department of Animal Biology, School of Biology and Center of Excellence in Phylogeny of Living Organisms, College of Science, University of Tehran, Tehran, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Sardari
authors.affiliation: Department of Animal Biology, School of Biology and Center of Excellence in Phylogeny of Living Organisms, College of Science, University of Tehran, Tehran, Iran.
authors.forename: Ameneh
authors.initials: A
authors.lastname: Rezayof
authors.affiliation: Neuroscience Research Center, Shahid Beheshti University of Medical Science, Tehran, Iran.
authors.forename: Fariba
authors.initials: F
authors.lastname: Khodagholi
authors.affiliation: Department of Neuroscience, School of Advanced Technologies in Medicine and Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad-Reza
authors.initials: MR
authors.lastname: Zarrindast
mesh_terms: D000679:Amygdala / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D001640:Bicuculline / Q000008:administration & dosage / Q000494:pharmacology; D004195:Disease Models, Animal; D058785:GABA-A Receptor Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D058787:GABA-A Receptor Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D008569:Memory Disorders / Q000188:drug therapy / Q000209:etiology / Q000378:metabolism*; D011939:Mental Recall / Q000187:drug effects / Q000502:physiology; D009118:Muscimol / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000378:metabolism*; D013315:Stress, Psychological / Q000150:complications*
chemical_list: D058785:GABA-A Receptor Agonists; D058787:GABA-A Receptor Antagonists; D011963:Receptors, GABA-A; D009118:Muscimol; D001640:Bicuculline