Behavioural Neuroscience Poster Session



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The Effect of Portacaval Anastomosis on Hippocampal EEG Activity

Lozeva, V. (Department of Pharmacology, University of Kuopio, Finland)
Valjakka, A. (Department of Pharmacology, University of Kuopio, Finland)
Hippeläinen, M. (Department of Surgery, University Hospital of Kuopio, Finland)
Tuomisto, L. (Department of Pharmacology, University of Kuopio, Finland)

Contact Person: Violina Lozeva (violina.lozeva@uku.fi)


Impairment of intellectual functions is a classic symptom of portal-systemic encephalopathy in humans. The hippocampal system is important for learning and memory both in humans and animals. Therefore, we chose to study hippocampal EEG properties in rats with portacaval anastomosis (PCA) at two consecutive time points, 1 month and 6 months after PCA. The tissue levels of histamine and tele-methylhistamine in hippocampus were also assayed. A decreasing trend in the overall power density and in the average power density of the 5-9 Hz frequency band (theta rhythm) of hippocampal EEG activity was apparent 1 month after PCA. This decrease had become significant 6 months after the operation. A significant, seven-fold increase in the levels of histamine and a two-fold elevation in the concentration of tele-methylhistamine were also observed in the PCA rats. In the sham rats, the levels of tele-methylhistamine correlated positively with the overall power density and with the power density of the 5 to 9 Hz frequency band, whereas no such correlation existed after PCA. We conclude that the hippocampal histamine system may play a role in the generation of hippocampal EEG activity in normal rats. However, it is unclear whether the hippocampal histamine system contributes to the decrease in EEG activity induced by PCA.

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Poster Number PAlozeva0424
Keywords: portacaval shunt, histamine, EEG, hippocampus, rats

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Lozeva, V.; Valjakka, A.; Hippeläinen, M.; Tuomisto, L.; (1998). The Effect of Portacaval Anastomosis on Hippocampal EEG Activity. Presented at INABIS '98 - 5th Internet World Congress on Biomedical Sciences at McMaster University, Canada, Dec 7-16th. Available at URL http://www.mcmaster.ca/inabis98/behavneuro/lozeva0424/index.html
© 1998 Author(s) Hold Copyright