Referenced in: none

Automatically associated channels: Kir6.2

Title: Pinacidil opens ATP-dependent K+ channels in cardiac myocytes in an ATP- and temperature-dependent manner.

Authors: C L Martin, K Chinn

Journal, date & volume: J. Cardiovasc. Pharmacol., 1990 Mar , 15, 510-4

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/1691378

Abstract
Pinacidil is an antihypertensive agent that has been found to increase potassium conductance. This study examined the type of K channel affected by pinacidil in cardiac myocytes. Pinacidil shortened the action potential duration in papillary muscle. The effect was reversible upon addition of glyburide, a known IKATP blocker. The effect of pinacidil was temperature-dependent. Action potential duration was shortened more rapidly and to a greater extent at 37 degrees C than at 23 degrees C. Whole-cell experiments showed that I-V curves lost rectification after pinacidil treatment. As with the action potential experiments, the effect was more rapid at 37 degrees C than at 23 degrees C. Rectification was restored after exposure to glyburide. The I-V curve generated after pinacidil exposure was similar to that observed by others after treatment with metabolic inhibitors that activate IKATP. The effect of pinacidil was also ATP-dependent. Addition of 5 mM ATP to the internal solution prevented activation of IKATP. These data indicate that pinacidil activates IKATP.