Cytochrome oxidase activity of the suprachiasmatic nucleus and pineal gland in rats with portacaval shunt.
Rhythmic behavioral and biochemical changes have been observed in both human and animal models with hepatic insufficiency. The basis of all these alterations is the principal endogenous pacemaker, the suprachiasmatic nucleus. The aim of this work, therefore, is to determine cytochrome c oxidase activity, a marker of neuronal activity and oxidative metabolism, in this nucleus in rats with portacaval shunt. In order to do this, this enzyme was histochemically marked and quantified by computer-assisted optical densitometry. Results show a reduced cytochrome oxidase activity in the suprachiasmatic nucleus in animals with portacaval shunts and, inversely, an increase in oxidative metabolism in the pineal gland, another circadian structure. However, the activity measured in a noncircadian brain structure, the hippocampus, which served as a control, showed no changes with surgery. Additionally, locomotor activity was assessed by actimeters and revealed a clearly reduced activity in animals with portacaval shunt. We conclude that the suprachiasmatic nucleus is possibly involved in the rhythmic changes associated with hepatic insufficiency.
López
Laudino
L
Laboratorio de Psicobiología, Universidad de Oviedo, Oviedo, Spain.
González-Pardo
Héctor
H
Cimadevilla
José Manuel
JM
Cavas
María
M
Aller
María A
MA
Arias
Jaime
J
Arias
Jorge L
JL
D000204:Activity Cycles / Q000502:physiology; D000704:Analysis of Variance; D000818:Animals; D001835:Body Weight / Q000502:physiology; D003576:Electron Transport Complex IV / Q000378:metabolism*; D006501:Hepatic Encephalopathy / Q000201:enzymology*; D006624:Hippocampus / Q000201:enzymology; D008099:Liver / Q000098:blood supply / Q000502:physiology; D008297:Male; D009043:Motor Activity / Q000502:physiology; D009929:Organ Size / Q000502:physiology; D010870:Pineal Gland / Q000201:enzymology*; D011167:Portacaval Shunt, Surgical; D051381:Rats; D017208:Rats, Wistar; D013493:Suprachiasmatic Nucleus / Q000166:cytology / Q000201:enzymology*; D013737:Testis / Q000502:physiology
D003576:Electron Transport Complex IV