Schedule-induced psychological stress and molecular structures of
cardiomyocytes.
Rupp, Heinz, Bernhard Maisch, and Christian G. Brilla.
Institute of Physiology, University of T[umlaut]ubingen and
Molecular Cardiology Lab, Division of Cardiology, University of
Marburg, Marburg, Germany
APStracts 3:0330R, 1996.
To establish a psychological stress model, we characterized in rats
the effects of chronic (5-6 wk) scheduled food pellet feeding (35
mg/80 s for 8 hr/d). Because the scheduled intake of pellets required
that rats have access to 80% of ad libitum intake, the effect of food
restriction was also examined by withholding food intermittently for
24 or 48 hr each followed by 24 hr free access to food. Cardiac
norepinephrine concentration was significantly increased (1076 +/-
169 vs. 693 +/- 107 ng/g, P<0.05) in rats subjected to pellet
feeding compared with pair-fed rats (same amount of pellets in one
portion) or 24 or 48 hr intermittently fasted rats; similarly, the
epinephrine content of adrenal glands was increased (P<0.05).
Left ventricular rate of sarcoplasmic reticulum Ca2+ uptake was
decreased (P<0.05) compared with pair-fed rats reaching values
observed for 24 hr fasted rats, while the proportion of [alpha]
-myosin heavy chains was only slightly reduced. Thus, the schedule
-induced stress arising from pellet feeding exhibits features of
stress models involving physical pain and appears to stimulate the
adrenergic system with subsequent impairment of Ca2+ cycling which is
typical of various heart diseases.
Received 26 January 1996; accepted in final form 2 September
1996.
APS Manuscript Number R45-6.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 19 September 1996