Elevated blood lactate is associated with increased motor cortex excitability.
No information has yet been provided about the influence of blood lactate levels on the excitability of the cerebral cortex, in particular, of the motor cortex. The aim of the present study was to examine the effects of high blood lactate levels, induced with a maximal cycling or with an intravenous infusion, on motor cortex excitability. The study was carried out on 17 male athletes; all the subjects performed a maximal cycling test on a mechanically braked cycloergometer, whereas 6 of them were submitted to the intravenous infusion of a lactate solution (3 mg/kg in 1 min). Before the exercise or the injection, at the end, as well as 5 and 10 min after the conclusion, venous blood lactate was measured and excitability of the motor cortex was evaluated by using the transcranial magnetic stimulation. In both of these experimental conditions, it was observed that an increase of blood lactate is associated with a decrease of motor threshold, that is, an enhancement of motor cortex excitability. We conclude by hypothesizing that in the motor cortex the lactate could have a protective role against fatigue.
Coco
Marinella
M
Department of Physiological Sciences, University of Catania, Catania, Italy.
Alagona
Giovanna
G
Rapisarda
Giuseppe
G
Costanzo
Erminio
E
Calogero
Roberto Antonio
RA
Perciavalle
Valentina
V
Perciavalle
Vincenzo
V
D000704:Analysis of Variance; D001786:Blood Glucose / Q000378:metabolism; D004569:Electroencephalography / Q000379:methods; D019054:Evoked Potentials, Motor / Q000187:drug effects / Q000502:physiology*; D015444:Exercise / Q000502:physiology; D006801:Humans; D019344:Lactic Acid / Q000097:blood* / Q000494:pharmacology; D008297:Male; D009044:Motor Cortex / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors; D050781:Transcranial Magnetic Stimulation / Q000379:methods; D055815:Young Adult
D001786:Blood Glucose; D019344:Lactic Acid