title: Effect of depolarizing and hyperpolarizing agents on the membrane potential difference of primary cultures of rabbit aorta vascular smooth muscle cells.
abstract: Vascular smooth muscle cells of rabbit aorta were enzymatically dispersed, kept in primary culture, and studied between days 1 and 7 in a bath rinsed with Ringer-like solution at 37 degrees C. The electrical membrane potential difference (PD) was measured with microelectrodes. The mean value of PD was -50 +/- 0.4 mV (n = 53). Cromakalim (BRL 34915), 1 mumol/l and 10 mumol/l, hyperpolarized the membrane potential by 9 +/- 1 mV (n = 11) and 15 +/- 1 mV (n = 53) respectively. Glibenclamide (10 mumol/l) abolished the hyperpolarizing effect of chromakalim (n = 6). Simultaneous addition of cromakalim and glibenclamide (both 10 mumol/l, n = 11) and glibenclamide itself (10 mumol/l, n = 7) had no effect on PD. In patch-clamp experiments in outside-out-oriented Ca(2+)-sensitive K+ channels, cromakalim increased the open probability (Po) only slightly and only with a cytosolic Ca2+ activity of 1 mumol/l. In all other series cromakalim had no effect on the Po of these channels. Forskolin (10 mumol/l) hyperpolarized PD by 6 +/- 1 mV (n = 13). The nucleotides UTP, ATP and ITP (10 mumol/l) depolarized PD by 12 +/- 1 mV (n = 7), 8 +/- 1 mV (n = 65) and 5 +/- 1 mV (n = 6) respectively. GTP, [alpha, beta-methylene]ATP and adenosine had no significant effect.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Physiologisches Institut, Albert-Ludwigs-Universität, Freiburg, Federal Republic of Germany.
authors.forename: H
authors.initials: H
authors.lastname: Pavenstädt
authors.forename: V
authors.initials: V
authors.lastname: Lindeman
authors.forename: S
authors.initials: S
authors.lastname: Lindeman
authors.forename: K
authors.initials: K
authors.lastname: Kunzelmann
authors.forename: M
authors.initials: M
authors.lastname: Späth
authors.forename: R
authors.initials: R
authors.lastname: Greger
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology / Q000187:drug effects*; D001578:Benzopyrans / Q000494:pharmacology*; D002417:Cattle / Q000097:blood / Q000196:embryology; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology*; D019806:Cromakalim; D005905:Glyburide / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects*; D009711:Nucleotides / Q000494:pharmacology*; D011758:Pyrroles / Q000494:pharmacology*; D011817:Rabbits
chemical_list: D001578:Benzopyrans; D009711:Nucleotides; D011758:Pyrroles; D019806:Cromakalim; D005576:Colforsin; D005905:Glyburide