Secretory immunoglobulin A and cardiovascular activity during mental arithmetic and paced breathing

The role of the autonomic nervous system in secretory immunoglobulin A (sIg A) responses to laboratory challenge was explored in a study in which sIgA and cardiovascular activity were recorded at rest and during mental arithme tic and paced breathing. These tasks were selected to preferentially engage the sympathetic and parasympathetic nervous systems, respectively. Mental arithmetic elicited a mixed pattern of increased alpha- and beta-adrenergic activity and a reduction in parasympathetic activity; diastolic blood pres sure, total peripheral resistance, and systolic blood pressure increased, p reejection period shortened, and heart rate variability decreased. In contr ast, paced breathing primarily elicited an increase in parasympathetic acti vity; heart rate variability increased. Mental arithmetic also provoked an increase in sIgA concentration but no change in saliva volume, whereas pace d breathing affected neither sIgA concentration nor saliva volume. These da ta suggest that sIgA responses to laboratory challenges are mediated by sym pathetic rather than parasympathetic processes.