Water Intake Reduces the Noradrenaline Release in the Median Preoptic Nucleus Area Caused by Angiotensin II Injected into the Subfornical Oragn in the Rat

概要

論文の詳細を見る
The present study was carried out to investigate the role of noradrenergic systems in the median preoptic nucleus (MnPO) in the drinking response caused by microinjection of angiotensin II (ANG II) into the subfornical organ (SFO) in the awake rat. Extracellular levels of noradrenaline (NA) in the region of theMnPO were monitored with in vivo microdialysis methods. Injections of ANG II (10^<-6> M,50 nl) into the SFO significantly increased NA release in the MnPO area. The increase in the NA release induced by the ANG II injection was significantly reduced by water ingestion. In urethane-anesthetized rats, injections of ANG II into the SFO produced an elevation in mean arterial pressure (M.A.P.). Intravenous infusions of metaraminol (5μg), on the other hand, slightly suppressed the release of NA in the MnPO area that accompanied an elevation in M.A.P. These results suggest that the noradrenergic system in the MnPO may be involved in the dipsogenic response induced by ANG II acting at the SFO.
鳴門教育大学の論文