K. Imai et al., Attenuation of methylation of catecholamines and treatment with a coenzymeof catechol-O-methyltransferase in spontaneously hypertensive rats (SHR), P JPN AC B, 75(7), 1999, pp. 224-227
Citations number
12
Categorie Soggetti
Multidisciplinary
Journal title
PROCEEDINGS OF THE JAPAN ACADEMY SERIES B-PHYSICAL AND BIOLOGICAL SCIENCES
We have previously demonstrated that the release of plasma norepinephrine (
NE) in response to blood pressure reduction induced by calcium antagonist w
as substantially decreased in spontaneously hypertensive rats (SHR), as com
pared to the age-matched normotensive Wistar Kyoto (WKY) rats. Here we exam
ined extraneuronal methylation of NE: to normetanephrine (NLN) by catechol-
O-methyl-transferase (COMT). In the face of an acute hypotension by benidip
ine, the ratio of the increase of NMN to the increase of NE in plasma was l
ower in SHR than in WKY rat. The finding suggests that the extraneuronal in
activation of the released NE is blunted in SHR, namely, COMT is deactivate
d in this hypertensive rats. To define the role of NE methylation in hypert
ension, S-adenosyl-L-methionine (SAMe; 1.0 mg/kg, i.v.), a coenzyme of COMT
, was administered to SHR. The treatment induced a greater antihypertensive
effect, along with a greater decrease of NE and a larger increase of NMN i
n SHR. The data suggest that SAMe may be used as a possible remedy for hype
rtension.