Angiotensin II in neuronal cultures from brains of normotensive and hypertensive rats

Primary neuronal cultures from 1-day-old rat brains, which contain angiotensin II (ANG II) immunoreactivity within the neurons and are capable of de novo synthesis of this immunoreactivity, have been used in this study to determine the nature of this immunoreactivity by high-performance liquid chromatography (HPLC). Neuronal cultures from the brains of normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive (SH) rats were found to contain ANG II immunoreactivity, which co-migrated with authentic ANG II on HPLC. The angiotensin detected in brain cultures was not derived from the growth medium, and its level was significantly decreased by incubating the cultures with captopril. A 71% decrease in the levels of ANG II was observed in neuronal cultures of SH rat brains compared with those from WKY controls. These observations show that differences in brain angiotensin between SH and WKY are present before differences in blood pressure are manifested.