Adrenaline levels in brain stem nuclei and effects of a PNMT inhibitor on spontaneously hypertensive rats.

The adrenaline content of specific brain stem areas was decreased in young (4 week-old) but not in adult (14 week-old) SHR. Some of these areas also showed increased PNMT activity, indicating a possible enhanced release or metabolism of adrenaline early in the development of the hypertension. Dopamine and noradrenaline levels, on the contrary, were not changed either in young or adult animals. Administration of a PNMT inhibitor to adult SHR resulted in a decrease of the blood pressure in SHR to control levels. These observations support the hypothesis of a participation of adrenergic mechanisms in the development of genetic hypertension, and indicate the possibility for the use of PNMT inhibitors as hypotensive agents.