title: Early life inflammatory pain induces long-lasting deficits in hippocampal-dependent spatial memory in male and female rats.
abstract: The present experiment tested the hypothesis that neonatal injury disrupts adult hippocampal functioning and that normal aging or chronic stress during adulthood, which are known to have a negative impact on hippocampal function, exacerbate these effects. Male and female Sprague-Dawley rats were given an intraplantar injection of the inflammatory agent carrageenan (1%) on the day of birth and their memory was tested in the hippocampal-dependent spatial water maze in adulthood and again in middle age. We found that neonatal injury impaired hippocampal-dependent memory in adulthood, that the effects of injury on memory were more pronounced in middle-aged male rats, and that chronic stress accelerated the onset of these memory deficits. Neonatal injury also decreased glucocorticoid receptor mRNA in the dorsal CA1 area of middle-aged rats, a brain region critical for spatial memory. Morphine administration at the time of injury completely reversed injury-induced memory deficits, but neonatal morphine treatments in the absence of injury produced significant memory impairments in adulthood. Collectively, these findings are consistent with our hypothesis that neonatal injury produces long-lasting disruption in adult hippocampal functioning.
authors.affiliation: Neuroscience Institute, Georgia State University, P.O. Box 5030, Atlanta, GA 30302-5030, United States. Electronic address: yogawa1@student.gsu.edu.
authors.forename: Yoko O
authors.initials: YO
authors.lastname: Henderson
authors.affiliation: Neuroscience Institute, Georgia State University, P.O. Box 5030, Atlanta, GA 30302-5030, United States. Electronic address: victoria@umn.edu.
authors.forename: Nicole C
authors.initials: NC
authors.lastname: Victoria
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Yerkes National Primate Center, Emory University School of Medicine, 954 Gatewood Rd., Atlanta, GA 30322, United States; Center for Translational Social Neuroscience, Yerkes National Primate Center, Emory University School of Medicine, 954 Gatewood Rd., Atlanta, GA 30322, United States. Electronic address: inouek1120@gmail.com.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Inoue
authors.affiliation: Neuroscience Institute, Georgia State University, P.O. Box 5030, Atlanta, GA 30302-5030, United States. Electronic address: amurphy@gsu.edu.
authors.forename: Anne Z
authors.initials: AZ
authors.lastname: Murphy
authors.affiliation: Neuroscience Institute, Georgia State University, P.O. Box 5030, Atlanta, GA 30302-5030, United States; Department of Psychology, Georgia State University, P.O. Box 5010, Atlanta, GA 30302-5010, United States. Electronic address: mbparent@gsu.edu.
authors.forename: Marise B
authors.initials: MB
authors.lastname: Parent
mesh_terms: D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D005260:Female; D006624:Hippocampus / Q000378:metabolism / Q000503:physiopathology*; D007249:Inflammation / Q000150:complications*; D008297:Male; D008569:Memory Disorders / Q000209:etiology*; D009020:Morphine / Q000008:administration & dosage; D010146:Pain / Q000209:etiology / Q000503:physiopathology* / Q000523:psychology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011965:Receptors, Glucocorticoid / Q000378:metabolism; D012737:Sex Factors; D065852:Spatial Memory / Q000187:drug effects / Q000502:physiology*; D013315:Stress, Psychological / Q000150:complications*
chemical_list: D012333:RNA, Messenger; D011965:Receptors, Glucocorticoid; D009020:Morphine
keywords: Chronic stress; Early life pain; Glucocorticoid receptors; Morphine; Sex differences; Spatial water maze