Lactation alters the effects of conditioned stress on immune
function.
Shanks, Nola, Alex Kusnecov, Michael Pezzone, Jonathan Berkun &
Bruce S. Rabin.
Department of Medicine, University of Bristol, Bristol Royal
Infirmary Labs, Marlborough Street, Bristol, UK BS2 8HW, Division of
Clinical Immunopathology, Departments of Pathology and Medicine,
University of Pittsburgh Medical Centre, 200 Lothrop Street,
Pittsburgh, Pennsylvania, 15213-2582 USA
APStracts 3:0304R, 1996.
During lactation endocrine function is altered and stress responses
are dampened. Stress effects on immune function are partially
determined by endocrine factors, therefore, we assessed whether
stress similarly alters immune function during lactation. Sprague
-Dawley rats were conditioned by exposure to a tone paired with
footshock (2 sessions 16 shocks each) prior to breeding or were left
undisturbed. Lactating (Day 10) (LAC) and nonlactating diestrous
virgin controls (C) were sacrificed immediately following re-exposure
to the tone or removal from their homecage. Plasma corticosterone
stress responses were dampened in LAC relative to C animals.
Peripheral blood lymphocyte proliferation to T-cell receptor antibody
stimulation was reduced to a similar extent in both experimental
groups. Conditioned-stress reduced splenocyte proliferation and
increased nitrite accumulation in C animals, but not in LAC animals.
Mesenteric lymph node lymphocyte proliferation was significantly
increased following stress in LAC compared to Cs. Both plasma
interleukin-6 and phytohaemaglutinin stimulated splenic IL-6
production were increased in LAC animals compared to Cs following
stress exposure. These data indicate that stress-induced alterations
may be determined by different regulatory mechanisms within immune
compartments and that these effects depend on the physiological state
of the organism.
Received 30 August 1995; accepted in final form 22 July 1996.
APS Manuscript Number R541-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 29 August 1996