Aminopropionic acid receptors in paraventricular nucleus mediate pressor and vasopressin responses to endothelin-1 in subfornical organ.

Exp Biol Med (Maywood). 2006 Jun;231(6):1075-80.
Rossi NF, Chen H.
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Departments of Medicine and Physiology, Wayne State University School of Medicine and John D. Dingell VA Medical Center, Detroit, Michigan, USA.

Previously it has been shown that endothelin (ET-1) elicits pressor response and induces secretion of vasopressin (AVP). In this article the authors hypothesize that the pressor response and AVP secretion in response to ET-1 microinjection into subfornical organ (SFO) are mediated by glutamatergic receptor within the PVN. The reason the authors chose glutamatergic receptors is because they are shown to mediate ET-1-induced AVP secretion in vitro. In this study sinoaortic denervated male Long Evans rats were implanted with icv cannulae bilaterally in the SFO and PVN. ET-1 was directly injected into the SFO resulting in an increase in mean arterial pressure (MAP) and mean plasma AVP level, these changes were blocked by selective ET (A) inhibition. Pretreatment with an NMDA blocker diclozipine into PVN bilaterally showed no changes in MAP and MPV. However, when 6-cyano-7-nitroquinoxaline-2,3-dione was injected bilaterally in the PVN prevented the pressor response and also inhibited AVP secretion. In conclusion both the pressor response and AVP secretion in response to ET-1 acting at the SFO are mediated by a non-NMDA, most likely an aminopropionic acid glutamatergic receptor within the PVN.

-Madhan