OPIOID PEPTIDE MODULATION OF CIRCULATORY AND ENDOCRINE RESPONSE TO MENTAL STRESS IN HUMANS

Healthy subjects were classified according to their percent increase i n systolic blood pressure (SBP) after mental arithmetic test (MAT) as low (Delta SBP 9.3-15.1%, n = 15) and high (Delta SBP 35.1-45.4%, n = 15) responders. During MAT, low responders showed significantly (p < 0 .01) increased plasma levels of beta-endorphin, cortisol, catecholamin es, and atrial natriuretic factor (ANF) and decreased levels of endoth elin-1, whereas high responders showed increased (p < 0.01) levels of Metenkephalin, dynorphin B, and catecholamines. Pretreatment with nalo xone hydrochloride enhanced (p < 0.01) SEP, heart rate, noradrenaline, cortisol, and endothelin-1 levels, and reduced (p < 0.01) ANF in low responders in response to MAT, whereas it decreased (p < 0.01) hemodyn amic parameters, noradrenaline, and endothelin-1 in high responders. T he individual differences in hemodynamic and endocrine responses to MA T may depend on a different activation of the endogenous opioid. syste m. (C) 1997 Elsevier Science Inc.