Inhibition of histamine synthesis influences the development of hypertension in spontaneously hypertensive rats.

Young (3-week old) and adult (7-week old) spontaneously hypertensive rats (SHR) and normotensive rats (WKY) were treated with alpha-fluoromethylhistidine (alpha-FMH) for 29 and 13 days, respectively. Treatment of SHR and WKY with alpha-FMH led to a pronounced decrease in the histidine decarboxylase activity and in the histamine concentration in all brain areas studied. In adult SHR, the development of hypertension was not influenced by alpha-FMH. In young SHR, alpha-FMH elicited a transient delay in the development of hypertension followed by a short-lasting tendency for increased blood pressure. It is concluded that histaminergic neurons of the brain play, if at all, only a secondary role in the development of hypertension in SHR.