title: Basic electrical properties of in situ endothelial cells of small pulmonary arteries during postnatal development.
abstract: Small pulmonary arteries are the major determinants of pulmonary artery pressure and vascular resistance. Their endothelium modulates pulmonary resistance, remodeling, and blood fluidity. We developed a method that provides access to the luminal surface of small pulmonary arteries of rat and allows the patch-clamp study of electrical properties of in situ endothelium. At birth, the membrane was predominantly permeable for K(+), showing a resting potential of -70 mV. This conductance was not voltage-dependent and was insensitive to standard blockers of K(+) channels such as tetraethylammonium, charybdotoxin, and 4-aminopyridine. The first 22 d of development were accompanied by an additional expression of a Cl(-) conductance, increasing membrane potential to -45 mV. Acidosis reduced K(+) conductance and depolarized the membrane, whereas alkalosis resulted in hyperpolarization. Two-electrode recordings revealed tight electrical coupling (83%) between neighboring cells in the circumferential direction of the artery. The electrotonic length constant for endothelium was 13.3 microm, indicating that most cells in one cross section of a small artery are well coupled. Thus, the resting membrane conductances in small pulmonary artery endothelial cells change with postnatal development and are modulated by pH.
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, Justus-Liebig-University, Giessen, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Olschewski
authors.forename: H
authors.initials: H
authors.lastname: Olschewski
authors.forename: M E
authors.initials: ME
authors.lastname: Bräu
authors.forename: G
authors.initials: G
authors.lastname: Hempelmann
authors.forename: W
authors.initials: W
authors.lastname: Vogel
authors.forename: B V
authors.initials: BV
authors.lastname: Safronov
mesh_terms: D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D002450:Cell Communication / Q000502:physiology; D002712:Chlorides / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D007473:Ion Channels / Q000037:antagonists & inhibitors; D008564:Membrane Potentials / Q000502:physiology; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000378:metabolism; D011651:Pulmonary Artery / Q000166:cytology / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D051381:Rats; D019789:Tetraethylammonium / Q000494:pharmacology
chemical_list: D002712:Chlorides; D007473:Ion Channels; D019789:Tetraethylammonium; D011188:Potassium