Sympathetic vasoconstrictor responses in multiple sclerosis with thermoregulatory dysfunction

Centrally and locally mediated sympathetic vasoconstrictor responses in skeletal muscle and subcutaneous tissue were studied in six patients with definite multiple sclerosis and severely affected thermoregulatory sweating. The purpose of the study was to evaluate vasomotor function in patients with pronounced thermoregulatory dysfunction and to differentiate between locally and centrally elicited vasomotor reflexes in two different tissues. The method used, the 133-Xenon washout technique, makes such a distinction possible. In spite of the severe sweating disturbances, we found centrally and locally mediated sympathetic vasomotor reflexes to be preserved in skeletal muscle and subcutaneous tissue. The results support the view that sudomotor and vasomotor functions are independently controlled. Previously described differences in sympathetic vasoconstrictor responses in skeletal muscle and subcutaneous tissue in several other neurological disorders are not present in patients with multiple sclerosis, based on our results.