title: Effects of voluntary exercise on hippocampal long-term potentiation in morphine-dependent rats.
abstract: This study was designed to examine the effect of voluntary exercise on hippocampal long-term potentiation (LTP) in morphine-dependent rats. The rats were randomly distributed into the saline-sedentary (Sal/Sed), the dependent-sedentary, the saline-exercise (Sal/Exc), and the dependent-exercise (D/Exc) groups. The Sal/Exc and the D/Exc groups were allowed to freely exercise in a running wheel for 10 days. The Sal/Sed and the morphine-sedentary groups were kept sedentary for the same extent of time. Morphine (10 mg/kg) was injected bi-daily (12 h interval) during 10 days of voluntary exercise. On day 11, 2h after the morphine injection, the in vivo LTP in the dentate gyrus of the hippocampus was examined. The theta frequency primed bursts were delivered to the perforant path for induction of LTP. Population spike (PS) amplitude and the field excitatory post-synaptic potentials (fEPSP) slope were measured as indices of increase in synaptic efficacy. Chronic morphine increased the mean basal EPSP, and augmented PS-LTP. Exercise significantly increased the mean baseline EPSP and PS responses, and augmented PS-LTP in both saline and morphine-treated groups. Moreover, the increase of PS-LTP in the morphine-exercise group was greater (22.5%), but not statistically significant, than that of the Sal/Exc group. These results may imply an additive effect between exercise and morphine on mechanisms of synaptic plasticity. Such an interaction between exercise and chronic morphine may influence cognitive functions in opiate addicts.
authors.affiliation: Department of Physiology, School of Medical Sciences, Tarbiat Modares University, Tehran, Iran; Laboratory of Learning and Memory, Research Center and Department of Physiology, School of Medicine, Semnan University of Medical Sciences, Semnan, Iran.
authors.forename: H
authors.initials: H
authors.lastname: Miladi-Gorji
authors.affiliation: Laboratory of Learning and Memory, Research Center and Department of Physiology, School of Medicine, Semnan University of Medical Sciences, Semnan, Iran. Electronic address: Rashidy-pour@sem-ums.ac.ir.
authors.forename: A
authors.initials: A
authors.lastname: Rashidy-Pour
authors.affiliation: Department of Physiology, School of Medical Sciences, Tarbiat Modares University, Tehran, Iran. Electronic address: fatolahi@modares.ac.ir.
authors.forename: Y
authors.initials: Y
authors.lastname: Fathollahi
authors.affiliation: Department of Physiology, School of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
authors.forename: S
authors.initials: S
authors.lastname: Semnanian
authors.affiliation: Laboratory of Learning and Memory, Research Center and Department of Physiology, School of Medicine, Semnan University of Medical Sciences, Semnan, Iran; Department of Medical Physics, School of Medicine, Semnan University of Medical Sciences, Semnan, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Jadidi
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D004195:Disease Models, Animal; D004558:Electric Stimulation; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D006624:Hippocampus / Q000503:physiopathology*; D017774:Long-Term Potentiation / Q000502:physiology*; D008297:Male; D009021:Morphine Dependence / Q000473:pathology* / Q000534:rehabilitation*; D010805:Physical Conditioning, Animal; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
keywords: ANOVA; AP; Anterior-Posterior; BDNF; D/Exc; D/Sed; DG; DV; Dorssal-ventral; I/O; LTP; ML; Medial-lateral; N-methyl-d-aspartate; NMDA; PBs; PP; PS; Sal/Exc; Sal/Sed; TrkB; analysis of variance; brain-derived neurotrophic factor; dentate gyrus; dependent–exercise; dependent–sedentary; fEPSP; field excitatory post-synaptic potentials; hippocampus; input/output; long-term potentiation; morphine exposure; perforant bath; population spike; primed bursts; saline–exercise; saline–sedentary; tyrosine kinase B; voluntary exercise