title: Sevoflurane anesthesia induces neither contextual fear memory impairment nor alterations in local population connectivity of medial prefrontal cortex local field potentials networks in aged rats.
abstract: Sevoflurane has been found to increase apoptosis and pathologic markers associated with Alzheimer disease, provoking concern over their potential contribution to postoperative cognitive dysfunction. This study aimed to determine the effects of sevoflurane on contextual fear memory of aged rats and to characterize local population connectivity of local field potentials (LFPs) in medial prefrontal cortex (mPFC) of aged rats during contextual fear memory. Eighteen-month-old male SD rats were implanted with one multichannel electrode array in mPFC. The aged rats were divided into control group, sevoflurane group (1 MAC sevoflurane for 2 h) and surgical group with 1.0 MAC sevoflurane for 2 h. We then assessed the effect of the anesthesia on contextual fear memory, and alterations in the local population connectivity of mPFC LFP networks by partial directed coherence (PDC). Surgery impaired contextual fear memory and reduced local population connectivity of mPFC LFP networks in aged rats at day 1 after the surgery and anesthesia. 1 MAC Sevoflurane anesthesia induced neither contextual fear memory impairment nor alterations in local population connectivity of mPFC LFP networks in aged rats when tested 1, 7, 15 and 30 days after exposure (P > 0.05). PDC values of theta band mPFC LFPs became strongly increased during contextual fear memory at 1, 7, 15, and 30 days after anesthesia. Our results suggest that 1 MAC sevoflurane anesthesia does not induce contextual fear memory impairment in aged rats and suggest that the increased local population connectivity in theta bands LFPs of mPFC plays a role in contextual fear memory.
authors.affiliation: Laboratory of Neurobiology in Medicine, School of Biomedical Engineering, Tianjin Medical University, 22 Qi Xiang Tai Road, Tianjin, 300070, China.
authors.forename: Xinyu
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Anesthesiology, Tianjin Central Hospital of Gynecology and obstetrics, 156 San Ma Road, Tianjin, 300191, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Laboratory of Neurobiology in Medicine, School of Biomedical Engineering, Tianjin Medical University, 22 Qi Xiang Tai Road, Tianjin, 300070, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Tian
authors.affiliation: Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin Institute of Anesthesiology, 154 An Shan Road, Tianjin, 300050, China.
authors.forename: Guolin
authors.initials: G
authors.lastname: Wang
mesh_terms: D000375:Aging / Q000187:drug effects* / Q000502:physiology; D018685:Anesthetics, Inhalation / Q000008:administration & dosage; D000818:Animals; D003213:Conditioning, Psychological / Q000187:drug effects / Q000502:physiology; D005239:Fear / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008568:Memory / Q000187:drug effects* / Q000502:physiology; D008569:Memory Disorders / Q000139:chemically induced; D008738:Methyl Ethers / Q000008:administration & dosage*; D009415:Nerve Net / Q000187:drug effects* / Q000502:physiology; D017397:Prefrontal Cortex / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D000077149:Sevoflurane
chemical_list: D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane
keywords: Sevoflurane; aged; contextual fear memory; local field potentials; local population connectivity