Diurnal rhythm returns to normal after elimination of portacaval
shunting.
Hawkins, Paul A., Mary R. Dejoseph, and Richard A. Hawkins.
Department of Physiology and Biophysics, Finch University of Health
Sciences/ The Chicago Medical School, 3333 Green Bay Road, North
Chicago, IL 60064-3095
APStracts 4:0261E, 1997.
Previous studies showed portacaval shunting causes metabolic and
behavioral changes in rats. Most metabolic changes reversed within 1
to 2 weeks after restoration of normal circulation. However, the rate
of cerebral glucose metabolism (CMRGlc) remained depressed in some
areas. The question arose whether complete recovery was possible.
Therefore, a long-term behavioral study was undertaken to determine
the time course of recovery. Diurnal activity was monitored for 48
hours each week over a period of 14 weeks: 2 weeks before shunting, 6
weeks after shunting, and 6 weeks after restoration of normal hepatic
circulation. Nighttime activity was depressed within 1 week of
shunting and did not change. Normal circulation to liver was
reestablished after 6 weeks. The diurnal cycle was normal 3 weeks
later. Thus, while recovery of the diurnal rhythm is possible, the
relatively long period necessary suggests the correction of a
significant structural or chemical abnormality. A study of CMRGlc was
made using the behavioral study as an index of the time necessary for
recovery. CMRGlc returned to normal throughout brain 6 weeks
following cessation of shunting except in the hippocampus and
amygdala (7-8% decrease).
Received 6 August 1997; accepted in final form 12 November 1997.
APS Manuscript Number E372-7.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 12 December 1997