CONCOMITANT EVALUATION OF PLASMA GALANIN AND CATECHOLAMINE LEVELS DURING A COLD PRESSOR TEST IN HEALTHY-HUMAN MALE AND FEMALE SUBJECTS

The neuropeptide galanin (GAL) is localized in the peripheral and cent ral nervous systems as well as in the adrenal medulla where it coexist s with catecholamines. We evaluated the changes in GAL plasma levels a s well as systolic and diastolic blood pressures and in the plasma lev els of epinephrine and norepinephrine (NE) in normal human male and re gularly menstruating female subjects during the activation of the symp athoadrenal system by a cold presser test, The test was performed by i mmersing the hand of the subject in 1 degrees C cold water for 4 min, Blood samples were collected both under basal conditions and at subseq uent intervals during the cold stimulus as well as at the end of the r ecovery phase, The values were compared with those obtained when the s ame subjects were sham tested. As expected, systolic and diastolic blo od pressures increased in both sexes during the cold test; the systoli c blood pressure values were significantly (p < 0.05) higher in males. Epinephrine and NE levels rose significantly above baseline in both m ale and female subjects after the cold stimulus; the NE increments wer e significantly (p < 0.05) higher in males. The basal GAL levels were found to be variable but not sexually dimorphic, In both sexes, during cold stimulus and recovery phase, GAL values were found to be not sig nificantly different from those detected during the sham test. These r esults demonstrate that the release of GAL in peripheral blood is not associated with that of catecholamines in response to the cold presser test.