title: Altered Acoustic Startle Reflex, Prepulse Inhibition, and Peripheral Brain-Derived Neurotrophic Factor in Morphine Self-Administered Rats.
abstract: Previous studies suggested that opiate withdrawal may increase anxiety and disrupt brain-derived neurotrophic factor function, but the effects of i.v. morphine self-administration on these measures remain unclear.
  
  
  
  Adult male Sprague-Dawley rats were implanted with a catheter in the jugular vein. After 1 week of recovery, the animals were allowed to self-administer either i.v. morphine (0.5 mg/kg per infusion, 4 h/d) or saline in the operant conditioning chambers. The acoustic startle reflex and prepulse inhibition were measured at a baseline and on self-administration days 1, 3, 5, and 7 (1- and 3-hour withdrawal). Blood samples were collected on self-administration days 3, 5, and 7 from separate cohorts of animals, and the levels of brain-derived neurotrophic factor and corticosterone were assayed using the enzyme-linked immunosorbent assay method.
  
  
  
  Compared with the saline group, the morphine self-administration group showed hyper-locomotor activity and reduced defecation during the self-administration. The morphine self-administration increased acoustic startle reflex at 1-hour but not 3-hour withdrawal from morphine and disrupted prepulse inhibition at 3-hour but not 1-hour withdrawal. The blood brain-derived neurotrophic factor levels were decreased in the morphine self-administration group at self-administration days 3 and 5, while the corticosterone levels remained unchanged throughout the study.
  
  
  
  The current findings suggest that spontaneous withdrawal from i.v. morphine self-administration may have transient effects on acoustic startle, sensorimotor gating, and peripheral brain-derived neurotrophic factor levels, and these changes may contribute to the adverse effects of opiate withdrawal.
authors.affiliation: Department of Acupuncture, Moxibustion and Acupoint, College of Korean Medicine, Daegu Haany University, Daegu, Republic of Korea.|Department of Psychiatry, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
authors.forename: Bong Hyo
authors.initials: BH
authors.lastname: Lee
authors.affiliation: Department of Psychiatry, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.|Center for Study of Traumatic Stress, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
authors.forename: Thomas Y
authors.initials: TY
authors.lastname: Park
authors.affiliation: Department of Psychiatry, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
authors.forename: Erica
authors.initials: E
authors.lastname: Lin
authors.affiliation: Department of Psychiatry, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.|Center for Study of Traumatic Stress, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
authors.forename: He
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Physiology, College of Korean Medicine, Daegu Haany University, Daegu, Republic of Korea.
authors.forename: Chae Ha
authors.initials: CH
authors.lastname: Yang
authors.affiliation: Department of Psychiatry, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.|Center for Study of Traumatic Stress, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.|Daniel K. Inouye Graduate School of Nursing, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
authors.forename: Kwang H
authors.initials: KH
authors.lastname: Choi
mesh_terms: D000161:Acoustic Stimulation; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000097:blood*; D003216:Conditioning, Operant / Q000187:drug effects; D004797:Enzyme-Linked Immunosorbent Assay; D006854:Hydrocortisone / Q000097:blood; D008297:Male; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology*; D065808:Prepulse Inhibition / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013216:Reflex, Startle / Q000187:drug effects*; D012646:Self Administration; D013997:Time Factors
chemical_list: D000701:Analgesics, Opioid; D019208:Brain-Derived Neurotrophic Factor; D009020:Morphine; D006854:Hydrocortisone
keywords: acoustic startle reflex; brain-derived neurotrophic factor; corticosterone; i.v. morphine self-administration; opiate withdrawal; prepulse inhibition