PMID: 9431449Feb 12, 1998Paper

ATP-gated potassium channel activity of pulmonary resistance vessels in the lamb

Canadian Journal of Physiology and Pharmacology
J G TheisF Coceani

Abstract

There are conflicting reports on the role of ATP-gated potassium channels (KATP) in the perinatal pulmonary circulation. To investigate this issue, we have used isolated pulmonary resistance vessels from near-term fetal lambs and have tested levcromakalim and glybenclamide, respectively a KATP opener and blocker, on muscle tone at fetal and neonatal PO2, and under hypoxia. Levcromakalim (from 1 microM upwards) relaxed arteries and veins precontracted with a thromboxane A2 (TXA2) analogue (ONO-11113) at neonatal PO2. This effect was nearly completely inhibited by glybenclamide (10 microM) and NG-nitro-L-arginine methyl ester (L-NAME, 100 microM). Conversely, levcromakalim relaxed little arteries precontracted with activating solution (5 mM Ca2+ in K(+)-Krebs) or hypoxia. Equally modest was the response of endothelium-denuded, ONO-11113-contracted arteries. Glybenclamide (10 microM) by itself did not raise the basal tone of vessels, regardless of PO2. We conclude that fetal pulmonary resistance vessels have KATP channels. In the arteries, these channels are located in the endothelium, and their opening causes relaxation by promoting nitric oxide formation. However, this relaxing mechanism does not become active when PO2 is raised...Continue Reading

Citations

May 9, 2001·The Journal of Surgical Research·J R Gosche
Nov 1, 2001·Respiratory Research·N S Ghanayem, J B Gordon

❮ Previous
Next ❯

Related Concepts

Related Feeds

Antihypertensive Agents: Mechanisms of Action

Antihypertensive drugs are used to treat hypertension (high blood pressure) which aims to prevent the complications of high blood pressure, such as stroke and myocardial infarction. Discover the latest research on antihypertensive drugs and their mechanism of action here.