With an increasing body of evidence regarding GPCR oligomerization and its clinical implications over the last decade， the modulation and dynamics of GPCR homo- and hetero-oligomers has more recently become an area of intense research focus. Previously， our lab showed in vitro heteromer formation between angiotensin II receptor type 1 subtype a (AT1aR) and secretin receptor (SCTR)， which is involved in in vivo control of hyperosmolality-induced water drinking behavior. Because the secretin (SCT)/SCTR axis is crucial to the central actions of angiotensin II (ANGII) and both SCT and ANGII are capable of triggering vasopressin (Vp) release from hypothalamus， we investigated here the in vivo role of SCTR-AT... More
With an increasing body of evidence regarding GPCR oligomerization and its clinical implications over the last decade， the modulation and dynamics of GPCR homo- and hetero-oligomers has more recently become an area of intense research focus. Previously， our lab showed in vitro heteromer formation between angiotensin II receptor type 1 subtype a (AT1aR) and secretin receptor (SCTR)， which is involved in in vivo control of hyperosmolality-induced water drinking behavior. Because the secretin (SCT)/SCTR axis is crucial to the central actions of angiotensin II (ANGII) and both SCT and ANGII are capable of triggering vasopressin (Vp) release from hypothalamus， we investigated here the in vivo role of SCTR-AT1aR heteromer in regulating Vp release in hypothalamus using transmembrane peptides as tools. We showed that SCTR-AT1aR heteromer mediates stimulatory actions of both SCT and ANGII in hypothalamic Vp expression and release as well as neuronal activities via the immediate early gene cFos. The results from this study not only are consistent with our hypothesis that SCT and ANGII interact at the receptor level to mediate their water homeostatic activities but also provide evidence for in vivo functions of cross-class GPCR heteromers.-Mak， S. O. K.， Zhang， L.， Chow， B. K. C. In vivo actions of SCTR/AT1aR heteromer in controlling Vp expression and release via cFos/cAMP/CREB pathway in magnocellular neurons of PVN.
