Characteristic alterations in adrenal catecholamine contents in SHR, SHRSP, and WKY during development of hypertension and stroke.

The role of adrenal catecholamines (CAs) was investigated with regard to the etiology of hypertension and cerebral stroke in the spontaneously hypertensive rats-stroke prone (SHRSP). The adrenal CAs in SHRSP were measured by high performance liquid chromatography with an electrochemical detector or by gas-liquid chromatography with an electron capture detector and the findings were compared with those in the spontaneously hypertensive rats (SHR) and Wistar-Kyoto strain (WKY). It has been proposed that the facilitation of peripheral sympathetic norepinephrine (NE) neurons in the young animals may act as a trigger in the development of hypertension in the SHR. This was verified by estimating the adrenal NE contents in both SHRSP and SHR at 4 weeks of age. A deficiency in adrenal dopamine (DA) in 4-week-old SHRSP was also observed. This deficiency may contribute to the facilitation of the adrenal NE cell. SHRSP was clearly distinguished from SHR by comparing the adrenal catecholamine contents of each strain. The contents of all three CAS in SHRSP were similar to those in WKY during the development of hypertension, while the contents of epinephrine and DA in the SHR were much higher than those in the WKY. Only in SHRSP did the contents of all three CAs increase rapidly after the development of hypertension. These rapid increases may be related to stroke.