Portal-systemic encephalopathy (PSE) is associated with increased brain turnover of serotonin (5-HT) in vivo but the brain 5-HT output seems to be unaltered. Recent results suggest, however, that an augmented neocortical 5-HT release in experimental chronic PSE may prevail under certain conditions. In the present study, neocortical extracellular 5-HT and 5-hydroxyindoleacetic-3-acid (5-HIAA) levels were measured in portacaval shunted (PCS) rats and sham-operated controls following local administration of p-chloroamphetamine (pCA) and d-fenfluramine (dFEN), two specific 5-HT releasing agents. The basal neocortical extracellular 5-HT concentrations were unaltered and the 5-HIAA levels were elevated in experimental PSE, supporting an unchanged brain 5-HT output despite elevated brain 5-HT metabolism. Perfusion with pCA or dFEN (5 microM; one 20-min pulse) produced marked increases in brain 5-HT release both in PCS and sham-operated rats compared with corresponding basal values. While no difference in the 5-HT response to dFEN administration was seen between sham (5-HT levels increased by 330%) and PCS (500%) rats, a clear difference (p<0.05) in the brain 5-HT output was observed between the two experimental groups following pCA perfusion (sham, 1100% versus PCS, 1470%). These results support our previous contention of an enhanced neocortical 5-HT output in experimental chronic PSE under certain pharmacological conditions.
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J Chromatogr Sci
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Division of Chemical and Material Metrology, Korea Research Institute of Standards and Science, 267, Gajeong-ro, Yuseong-gu, Daejeon, 34113Republic of Korea.
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Department of Stem Cell Bioengineering, Mossakowski Medical Research Institute, Polish Academy of Sciences, Pawinskiego 5 Str, 02-106 Warsaw, Poland.
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Department of Pharmacology, University of Oxford, Oxford, UK.
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Institute of Food Science and Technology, College of Bioresources and Agriculture, National Taiwan University, Taipei, Taiwan.
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