Alterations in the field stimulation-induced release of endogenous norepinephrine from the coccygeal artery of spontaneously hypertensive and Wistar-Kyoto rats.

The field stimulation-induced release of endogenous NE from the isolated caudal artery from 5-6, 8-10 and 28-30 week old SHR resulted in a greater release of transmitter compared to age-matched WKY. The alpha 2-selective adrenoceptor antagonist, yohimbine produced a significant enhancement in the release of NE from both SHR and WKY of 5-6 and 10-12 and 28 week old WKY but release was attenuated in 28 week old SHR. It is concluded that the enhanced release of NE contributes to the development of hypertension in the SHR.