GPCR that does not act through opening of potassium channels is?
(A) Muscarinic M2 receptor (B) Dopamine D2 receptor (C) Serotonin 5 HT1 receptor (D) Angiotensin 1 receptor
(D) Ans. D. Angiotensin 1 receptor* Four G protein gated inwardly-rectifying potassium (GIRK) channel subunits have been identified in mammals: GIRK1, GIRK2, GIRK3, and GIRK4. The GIRK subunits come together to form GIRK ion channels.* Activation of the IKACh channels begins with release of acetylcholine (ACh) from the vagus nerve onto pacemaker cells in the hea.* ACh binds to the M2 muscarinic acetylcholine receptors, which interact with G proteins.