Elevated blood lactate is associated with increased motor cortex excitability

• Published in: Somatosensory & motor research Vol. 27; no. 1; pp. 1 - 8
• Main Authors: Coco, Marinella, Alagona, Giovanna, Rapisarda, Giuseppe, Costanzo, Erminio, Calogero, Roberto Antonio, Perciavalle, Valentina, Perciavalle, Vincenzo
• Format: Journal Article
• Language: English
• Published: England Informa UK Ltd 2010; Taylor & Francis
• Subjects: Analysis of Variance; Blood Glucose - metabolism; cortical excitability; Electroencephalography - methods; Evoked Potentials, Motor - drug effects; Evoked Potentials, Motor - physiology; Exercise - physiology; Humans; lactate infusion; Lactic Acid - blood; Lactic Acid - pharmacology; Male; maximal exercise; Motor Cortex - drug effects; Motor Cortex - physiology; Time Factors; transcranial magnetic stimulation; Transcranial Magnetic Stimulation - methods; Young Adult
• ISSN: 0899-0220; 1369-1651
• DOI: 10.3109/08990220903471765

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.