title: Chronic carbon monoxide enhanced IbTx-sensitive currents in rat resistance pulmonary artery smooth muscle cells.
abstract: Exogenous carbon monoxide (CO) can induce pulmonary vasodilation by acting directly on pulmonary artery (PA) smooth muscle cells. We investigated the contribution of K+ channels to the regulation of resistance PA resting membrane potential on control (PAC) rats and rats exposed to CO for 3 wk at 530 parts/million, labeled as PACO rats. Whole cell patch-clamp experiments revealed that the resting membrane potential of PACO cells was more negative than that of PAC cells. This was associated with a decrease of membrane resistance in PACO cells. Additional analysis showed that outward current density in PACO cells was higher (50% at +60 mV) than in PAC cells. This was linked to an increase of iberiotoxin (IbTx)-sensitive current. Chronic CO hyperpolarized membrane of pressurized PA from -46.9 +/- 1.2 to -56.4 +/- 2.6 mV. Additionally, IbTx significantly depolarized membrane of smooth muscle cells from PACO arteries but not from PAC arteries. The present study provides initial evidence of an increase of Ca2+-activated K+ current in smooth muscle cells from PA of rats exposed to chronic CO.
authors.affiliation: Laboratoire de Physiopathologie de la Paroi Artérielle, Faculté de Médecine, 37032 Tours, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Dubuis
authors.forename: Mathieu
authors.initials: M
authors.lastname: Gautier
authors.forename: Alexandre
authors.initials: A
authors.lastname: Melin
authors.forename: Manuel
authors.initials: M
authors.lastname: Rebocho
authors.forename: Catherine
authors.initials: C
authors.lastname: Girardin
authors.forename: Pierre
authors.initials: P
authors.lastname: Bonnet
authors.forename: Christophe
authors.initials: C
authors.lastname: Vandier
mesh_terms: D015761:4-Aminopyridine / Q000494:pharmacology; D000818:Animals; D001274:Atmospheric Pressure; D002248:Carbon Monoxide / Q000494:pharmacology*; D005260:Female; D008564:Membrane Potentials / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D018408:Patch-Clamp Techniques; D010455:Peptides / Q000494:pharmacology*; D011188:Potassium / Q000378:metabolism; D026902:Potassium Channel Blockers / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology; D011651:Pulmonary Artery / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar
chemical_list: D010455:Peptides; D026902:Potassium Channel Blockers; D015221:Potassium Channels; C064719:iberiotoxin; D002248:Carbon Monoxide; D015761:4-Aminopyridine; D011188:Potassium