Referenced in: none

Automatically associated channels: Kir2.3

Title: Modulation of K+ and Ca2+ currents in cultured neurons by an angiotensin II type 1a receptor peptide.

Authors: M Zhu, R R Neubig, S M Wade, P Posner, C H Gelband, C Sumners

Journal, date & volume: Am. J. Physiol., 1997 Sep , 273, C1040-8

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/9316425

Abstract
Angiotensin II (ANG II) inhibits delayed rectifier K+ current (IK) and stimulates total Ca2+ current (ICa) in neurons cocultured from newborn rat hypothalamus and brain stem, effects mediated via ANG II type 1 (AT1) receptors. Here, we identify potential G protein activator regions of the AT1 receptor responsible for initiating the intracellular changes that lead to alterations in these currents. Intracellular application into cultured neurons of a peptide corresponding to the third cytoplasmic loop of the AT1 receptor (AT1a/i3) mimicked the actions of ANG II on IK and ICa, whereas application of a peptide corresponding to the second cytoplasmic loop (AT1a/i2) did not alter these currents. This modulation of IK and ICa by AT1a/i3 involves intracellular messengers (G alpha q, protein kinase C, and intracellular Ca2+) that are identical to those involved in the modulation of IK and ICa following ANG II activation of AT1 receptors. These data provide functional evidence for a role of the third cytoplasmic loop of the AT1 receptor in G protein coupling and subsequent modulation of ion channel effectors.