Noradrenaline metabolism in the brain of rats with genetically determined hypertension (SHR)
Zukowska-Grójec, Z.
Kardiologia Polska 23(10): 881-891
1980
ISSN/ISBN: 0022-9032 PMID: 7463938 Document Number: 166596
Male rats (98) with genetically determined hypertension (SHR) and 106 Wistar rats with normotension aged 1, 3, 8 and 24 wk were studied. Noradrenaline (norepinephrine, NA) level was determined by a spectrophotofluorimetric method; the radioactivity level was determined by the 3H-NA method; and the total amount of 3H-3-methoxy-4-hydroxyphenylglycol (3H-MOPEG) and 3H-3,4-dihydroxyphenylglycol (3H-DOPEG) after administration of 3H-tyrosine i.p. using a radioisotope method. In SHR rats the NA level was lower than in control rats in the hindbrain from the 3rd wk of life and in the forebrain from the 8th wk on, and it decreased further. In the forebrain of SHR rats aged 8 wk with labile hypertension the level of 3H-NA was lower than in resting Wistar rats. After stress (20 min of forced running) in SHR rats the level of 3H-NA was not raised, but its breakdown to metabolites increased in contrast to control rats. At the time of stabilized hypertension, i.e., at 24 wk, increased conversion of 3H-NA to 3H-MOPEG in SHR rats was evident at rest. Lower NA level in the brain of SHR rats may be due to impaired synthesis or to increased metabolism of this substance to glycols. The disturbances increase with age, which may be important in the development and progression of hypertension.