Trait-like immunological and hematological measures in female rhesus across varied environmental conditions (1999)

Lilly, A. A., Mehlman, P. T., Higley, J.

Abstract

The immune measures were depressed at capture (excepting B cells), and during 7 months of single caging failed to return to normal levels associated with social housing [group of 5 females]. We thus conclude that single housing can produce significant, long-term features of immunosuppression. Capture produced significant increases in plasma cortisol, prolactin, and norepinephrine concentrations. Long periods of single caging produced significant increases in plasma prolactin concentrations, indicative of stress-induced anxiety. ... The observation that NE [norepinephrine] was significantly decreased during the latter portions of Single Cage Housing may be further, tentative physiological evidence for the occurrence of depression in these animals. .... As single caging continued, an increasing percentage of the animals showed withdrawal and depression as witnessed by crouching, huddling, and overall inactivity, clearly indicative of an 'inactive' or 'despair' phase commonly described.