Transforming growth factor-beta activated during exercise in brain depresses spontaneous motor activity of animals. Relevance To central fatigue.
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.
Inoue
K
K
Laboratory of Nutrition Chemistry, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.
Yamazaki
H
H
Manabe
Y
Y
Fukuda
C
C
Hanai
K
K
Fushiki
T
T
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
D000906:Antibodies; D007074:Immunoglobulin G; D016212:Transforming Growth Factor beta; D016222:Fibroblast Growth Factor 2; D004744:Enkephalin, Methionine; D013973:Thyrotropin-Releasing Hormone