1989 Volume 1 Issue 1-2 Pages 89-95
Age-related changes in the content of monoamines and their metabolites in four regions of the brain, cortex (CX), midbrain and thalamus (MB), hypothalamus (HT), and medulla oblongata (MO), were quantitatively assessed in spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) to determine the contribution of brain amines to the pathogenesis of hypertension. Seven-week-old SHR had a significantly higher concentration of noradrenaline (NA) in the CX, MB, and HT than age-matched WKY. On the other hand, at 12-weeks, NA contents in all four regions of SHR was significantly lower than in WKY. There was no difference in dopamine (DA) content in these four regions between 7-week-old SHR and age-matched WKY. But in 12-week-old SHR, DA content in CX and MB were significantly lower than in WKY. Seven-week-old SHR had significantly higher 5-HT concentration than WKY in the CX, MB, MO and HT, but at 12 weeks, 5-HT content in all these four brain regions of SHR were significantly lower than in WKY. The contents of MHPG and 5HIAA, which are metabolites of NA and 5-HT, respectively, in all four regions were lower in SHR than in WKY at 12 weeks. The contents of DOPAC and HVA, metabolites of DA, in the brain of 12-week-old SHR, also showed the same tendency. These results suggest that NA, DA and 5-HT in the brain may simultaneously affect the onset and development of hypertension in SHR.
