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Updated: Aug 11, 2026

A Convenient Method for Extraction and Analysis with High-Pressure Liquid Chromatography of Catecholamine Neurotransmitters and Their Metabolites
Published on: March 1, 2018
Low catechol-O-methyltransferase activity in the brain and blood pressure regulation
Mayumi Masuda1, Makoto Tsunoda, Kazuhiro Imai
1Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Abstract:
Catecholamines (CAs) are important hormones in regulating blood pressure both in centrally and peripheral sympathetic nerve endings. Production of CAs, release and inactivation are three components to regulate CAs level. We have reported that the inactivation of CAs by catechol-O-methyltransferase (COMT) in the liver is important in high blood pressure in spontaneously hypertensive rats (SHR). In the present study, we investigated central role of COMT in hypertension. We investigated COMT activities in cerebral cortex, cerebellum, hippocampus, brain stem, hypophysis, and hypothalamus of SHR and Wistar-Kyoto (WKY) rats. COMT activities were assessed by measuring normetanephrine with the use of norepinephrine as an endogenous substrate. Membrane-bound COMT activities in cerebral cortex were significantly reduced in SHR (19.1+/-1.8 pmol/min/mg protein) compared with WKY rats (25.0+/-3.3 pmol/min/mg protein). The ratio of concentrations of normetanephrine/norepinephrine in cerebral cortex was also lower in SHR than in WKY rats. Our results suggest that there is an association between MB-COMT in cerebral cortex and blood pressure regulation.
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