SUBCUTANEOUS NORADRENALINE CONCENTRATION INCREASE IN NORMAL SUBJECTS DURING COLD-EXPOSURE EVALUATED BY MICRODIALYSIS

Changes in local noradrenaline level in subcutaneous tissue were measured in four healthy males (23-33 years) during cold stimulation using a microdialysis technique. The subcutaneous dialysate noradrenaline concentration increased during cold exposure by a factor of 3.5 (P<0.003). A correction factor due to plasma overflow of noradrenaline to subcutaneous tissue was calculated from noradrenaline infusion studies. This correction had a minimal effect on the observed increase in dialysate noradrenaline concentration and the level of significance was only slightly altered after correction for plasma overflow. The microdialysis technique in combination with a sensitive radioenzymatic noradrenaline assay may be useful to assess changes in local subcutaneous noradrenaline level in man during physiological stimulation.