title: Transforming growth factor-beta activated during exercise in brain depresses spontaneous motor activity of animals. Relevance To central fatigue.
abstract: Intracerebroventricular administration into sedentary mice of the high molecular mass fraction of cerebrospinal fluid (CSF) from exercise-exhausted rats produced a decrease in spontaneous motor activity [K. Inoue, H. Yamazaki, Y. Manabe, C. Fukuda, T. Fushiki, Release of a substance that suppresses spontaneous motor activity in the brain by physical exercise, Physiol. Behav. 64 (1998) 185-190]. CSF from sedentary rats had no such effect. This suggests the presence of a substance regulating the urge for motion as a response to fatigue. A bioassay system using hydra, a freshwater coelenterate, showed an activity indistinguishable from transforming growth factor-beta (TGF-beta) in the CSF from exercise-fatigued rats, while not in that from sedentary rats. The increase in the concentration of active TGF-beta in the CSF from exercise-fatigued rat was also ascertained by another bioassay system using mink lung epithelial cells (Mv1Lu). Injection of TGF-beta into the brains of sedentary mice elicited a similar decrease in spontaneous motor activity in a dose-dependent manner. Increasing the exercise load on rats raised both the levels of active TGF-beta and the activity of depression on spontaneous motor activity of mice in the CSF of rats. Taken together, these results suggest that exercise increases active TGF-beta in the brain and it creates the feeling of fatigue and thus suppresses spontaneous motor activity.
authors.affiliation: Laboratory of Nutrition Chemistry, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Inoue
authors.forename: H
authors.initials: H
authors.lastname: Yamazaki
authors.forename: Y
authors.initials: Y
authors.lastname: Manabe
authors.forename: C
authors.initials: C
authors.lastname: Fukuda
authors.forename: K
authors.initials: K
authors.lastname: Hanai
authors.forename: T
authors.initials: T
authors.lastname: Fushiki
mesh_terms: D000818:Animals; D000906:Antibodies; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology*; D001681:Biological Assay; D001923:Brain Chemistry / Q000502:physiology; D004744:Enkephalin, Methionine / Q000494:pharmacology; D005221:Fatigue / Q000503:physiopathology*; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D006829:Hydra; D007074:Immunoglobulin G / Q000494:pharmacology; D008297:Male; D051379:Mice; D008845:Microinjections; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology*; D005082:Physical Exertion / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000134:cerebrospinal fluid* / Q000276:immunology / Q000494:pharmacology
chemical_list: D000906:Antibodies; D007074:Immunoglobulin G; D016212:Transforming Growth Factor beta; D016222:Fibroblast Growth Factor 2; D004744:Enkephalin, Methionine; D013973:Thyrotropin-Releasing Hormone