Dichloroacetate reduces sympathetic nerve responses to static exercise.

Area of Science:

• Exercise Physiology
• Neuroscience
• Biochemistry

Background:

• Lactic acid is a known stimulant of muscle metaboreceptors.
• Muscle sympathetic nerve activity (MSNA) increases during exercise.
• The precise role of lactic acid in exercise-induced MSNA is not fully understood.

Purpose of the Study:

• To investigate if inhibiting lactic acid production with dichloroacetate (DCA) can reduce MSNA during static forearm exercise.
• To explore the relationship between lactic acid accumulation and neural responses to exercise.

Main Methods:

• Seven subjects performed static forearm exercise with and without DCA administration.
• Lactic acid levels and MSNA were measured during exercise and post-exercise circulatory arrest.
• A control group received a saline infusion instead of DCA.

Main Results:

• DCA administration significantly attenuated the rise in forearm venous lactate.
• MSNA during post-handgrip circulatory arrest was significantly lower in the DCA trial compared to the control trial (51% reduction).
• Saline infusion in control subjects did not affect lactate or MSNA responses.

Conclusions:

• Dichloroacetate effectively inhibits lactic acid production during static exercise.
• The blunted lactate response is associated with a reduced MSNA response, supporting lactate's role in stimulating metaboreceptors.
• These findings highlight a link between metabolic byproducts and neural control of circulation during exercise.