RT Journal Article
SR Electronic
T1 Circulating Insulin-Like Growth Factor I Mediates Effects of Exercise on the Brain
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 2926
OP 2933
DO 10.1523/JNEUROSCI.20-08-02926.2000
VO 20
IS 8
A1 Eva Carro
A1 Angel Nuñez
A1 Svetlana Busiguina
A1 Ignacio Torres-Aleman
YR 2000
UL http://www.jneurosci.org/content/20/8/2926.abstract
AB Physical exercise increases brain activity through mechanisms not yet known. We now report that in rats, running induces uptake of blood insulin-like growth factor I (IGF-I) by specific groups of neurons throughout the brain. Neurons accumulating IGF-I show increased spontaneous firing and a protracted increase in sensitivity to afferent stimulation. Furthermore, systemic injection of IGF-I mimicked the effects of exercise in the brain. Thus, brain uptake of IGF-I after either intracarotid injection or after exercise elicited the same pattern of neuronal accumulation of IGF-I, an identical widespread increase in neuronal c-Fos, and a similar stimulation of hippocampal brain-derived neurotrophic factor. When uptake of IGF-I by brain cells was blocked, the exercise-induced increase on c-Fos expression was also blocked. We conclude that serum IGF-I mediates activational effects of exercise in the brain. Thus, stimulation of the uptake of blood-borne IGF-I by nerve cells may lead to novel neuroprotective strategies.