Muscarinic K+ Channel in the Heart
نویسندگان
چکیده
منابع مشابه
Muscarinic K+ Channel in the Heart
The membrane-delimited activation of muscarinic K+ channels by G protein beta gamma subunits plays a prominent role in the inhibitory synaptic transmission in the heart. These channels are thought to be heterotetramers comprised of two homologous subunits, GIRK1 and CIR, both members of the family of inwardly rectifying K+ channels. Here, we demonstrate that muscarinic K+ channels in neonatal r...
متن کاملShort-term desensitization of muscarinic K+ current in the heart.
Acetylcholine (ACh) rapidly increases cardiac K(+) currents (IKACh) by activating muscarinic K(+) (KACh) channels followed by a gradual amplitude decrease within seconds. This phenomenon is called short-term desensitization and its precise mechanism and physiological role are still unclear. We constructed a mathematical model for IKACh to examine the conditions required to reconstitute short-te...
متن کاملRole of receptor kinase in long-term desensitization of the cardiac muscarinic receptor-K+ channel system.
Desensitization of the cardiac muscarinic K+ channel was studied in cultured neonatal rat atrial cells and in Chinese hamster ovary (CHO) cells transfected with muscarinic receptor (HM(2)), G protein-coupled inward rectifying K+ channels 1 and 4, and G protein-coupled receptor kinase 2. In atrial cells incubated in 10 microM carbachol for 24 h, channel activity in cell-attached patches was subs...
متن کاملCocaine blockade of the acetylcholine-activated muscarinic K+ channel in ferret cardiac myocytes.
The effects of cocaine on the acetylcholine(ACh)-activated muscarinic K+ current (IK(ACh)) were assessed with the whole-cell patch-clamp technique in single atrial and left ventricular myocytes enzymatically isolated from adult ferret hearts. The density of IK(ACh) is almost 5 times greater in atrial cells than in left ventricular myocytes. Cocaine reversibly blocked IK(ACh) in a dose-dependent...
متن کاملOn the mechanism of G protein beta gamma subunit activation of the muscarinic K+ channel in guinea pig atrial cell membrane. Comparison with the ATP-sensitive K+ channel
The mechanism of G protein beta gamma subunit (G beta gamma)-induced activation of the muscarinic K+ channel (KACh) in the guinea pig atrial cell membrane was examined using the inside-out patch clamp technique. G beta gamma and GTP-gamma S-bound alpha subunits (G alpha *'s) of pertussis toxin (PT)-sensitive G proteins were purified from bovine brain. Either in the presence or absence of Mg2+, ...
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ژورنال
عنوان ژورنال: Journal of General Physiology
سال: 1998
ISSN: 0022-1295,1540-7748
DOI: 10.1085/jgp.112.2.199