Diurnal rhythm returns to normal after elimination of portacaval shunting.
Previous studies showed that portacaval shunting causes metabolic and behavioral changes in rats. Most metabolic changes reversed within 1-2 wk 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 h each week over a period of 14 wk: 2 wk before shunting, 6 wk after shunting, and 6 wk after restoration of normal hepatic circulation. Nighttime activity was depressed within 1 wk of shunting and did not change. Normal circulation to the liver was reestablished after 6 wk. The diurnal cycle was normal 3 wk later. Thus, although 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 the brain 6 wk after cessation of shunting except in the hippocampus and amygdala (7-8% decrease).
Hawkins
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PA
Department of Physiology and Biophysics, Finch University of Health Sciences, Chicago Medical School, Illinois 60064-3095, USA.
DeJoseph
M R
MR
Hawkins
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RA
D000641:Ammonia / Q000097:blood; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D001921:Brain / Q000378:metabolism*; D002940:Circadian Rhythm; D008102:Liver Circulation; D008297:Male; D011167:Portacaval Shunt, Surgical; D051381:Rats
D001786:Blood Glucose; D000641:Ammonia