Association between salivary Chromogranin A-like immunoreactivity secretion and sympathetic nerve activity

Abstract

  Previous studies have shown that catecholamines are major physiological markers of human stress, and are detectable not only in blood but also in saliva and urine. However the measurement of salivary catecholamines is difficult because of the low concentration and rapid enzymatic degradation.

  To investigate whether salivary chromogranin A instead of catecholamines reflects short-term changes of sympathetic nervous activity, we simultaneously measured salivary chromogranin A and plasma catecholamines concentrations at rest and immediately after bicycle ergometry in 13 healthy adults, using an enzyme immunosorbent assay with chromogranin A like immunoreactivity（CgA-like IR）. Salivary CgA-like IR levels significantly increased after cyclic exercise, and related either to blood noradrenaline concentrations or to heart rates（p<0.05）. Moreover, the ratio of salivary CgA-like IR concentrations was significantly correlated with the ratio of heart rates after cyclic exercise of the different workload（p<0.05）. These results indicate that salivary CgA-like IR reflects short-term changes in the activity of the cardiac sympathetic nerves, and may be more useful than salivary catecholamines. Therefore, salivary CgA-like IR can be used as an index of acute alterations in this system.