Advanced

Effects of polyamines on voltage-activated calcium channels in guinea-pig intestinal smooth muscle

Gomez, Maria LU and Hellstrand, Per LU (1995) In Pflügers Archiv 430(4). p.501-507
Abstract
Effects of polyamines on the spontaneous mechanical and electrical activity of guinea-pig intestinal smooth muscle were studied. Spermine and spermidine inhibited action potential generation and contractions, while putrescine had no effect. Single smooth muscle cells were isolated from the longitudinal muscle layer of the guinea-pig ileum. Whole-cell voltage-clamp experiments were carried out to investigate the effects of polyamines on current through voltage-activated Ca2+ channels. Spermine and spermidine (0.1-1 mM) reduced the inward current in a concentration-dependent manner. Spermine blocked current activated by the dihydropyridine agonist BAY K 8644 (1 microM), whereas no additional inhibition by spermine was seen after blockage of... (More)
Effects of polyamines on the spontaneous mechanical and electrical activity of guinea-pig intestinal smooth muscle were studied. Spermine and spermidine inhibited action potential generation and contractions, while putrescine had no effect. Single smooth muscle cells were isolated from the longitudinal muscle layer of the guinea-pig ileum. Whole-cell voltage-clamp experiments were carried out to investigate the effects of polyamines on current through voltage-activated Ca2+ channels. Spermine and spermidine (0.1-1 mM) reduced the inward current in a concentration-dependent manner. Spermine blocked current activated by the dihydropyridine agonist BAY K 8644 (1 microM), whereas no additional inhibition by spermine was seen after blockage of dihydropyridine-sensitive channels by nifedipine (0.1 microM). Inhibition by spermine or spermidine did not shift the peak of the current voltage relation of the inward current. Steady-state activation and inactivation relationships were not affected and thus the amplitude, but not the voltage dependence, of the window current responsible for Ca2+ inflow during sustained depolarization was affected. Putrescine (1 mM) had no significant effect on the inward current. These results suggest that spermine and spermidine inhibit contraction in spontaneously active intestinal smooth muscle by inhibiting Ca2+ current responsible for generation of action potentials. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Intestinal smooth muscle, Whole-cell voltage clamp, Ca2+ channels, Polyamines, Spermine, Spermidine, Putrescine
in
Pflügers Archiv
volume
430
issue
4
pages
501 - 507
publisher
Springer
external identifiers
  • pmid:7491276
  • scopus:0029051791
ISSN
0031-6768
DOI
10.1007/BF00373886
language
English
LU publication?
yes
id
6d5e8d62-ee2f-4161-9237-e3a26b98e2c6 (old id 1108868)
date added to LUP
2008-07-24 17:27:52
date last changed
2017-01-01 07:18:13
@article{6d5e8d62-ee2f-4161-9237-e3a26b98e2c6,
  abstract     = {Effects of polyamines on the spontaneous mechanical and electrical activity of guinea-pig intestinal smooth muscle were studied. Spermine and spermidine inhibited action potential generation and contractions, while putrescine had no effect. Single smooth muscle cells were isolated from the longitudinal muscle layer of the guinea-pig ileum. Whole-cell voltage-clamp experiments were carried out to investigate the effects of polyamines on current through voltage-activated Ca2+ channels. Spermine and spermidine (0.1-1 mM) reduced the inward current in a concentration-dependent manner. Spermine blocked current activated by the dihydropyridine agonist BAY K 8644 (1 microM), whereas no additional inhibition by spermine was seen after blockage of dihydropyridine-sensitive channels by nifedipine (0.1 microM). Inhibition by spermine or spermidine did not shift the peak of the current voltage relation of the inward current. Steady-state activation and inactivation relationships were not affected and thus the amplitude, but not the voltage dependence, of the window current responsible for Ca2+ inflow during sustained depolarization was affected. Putrescine (1 mM) had no significant effect on the inward current. These results suggest that spermine and spermidine inhibit contraction in spontaneously active intestinal smooth muscle by inhibiting Ca2+ current responsible for generation of action potentials.},
  author       = {Gomez, Maria and Hellstrand, Per},
  issn         = {0031-6768},
  keyword      = {Intestinal smooth muscle,Whole-cell voltage clamp,Ca2+ channels,Polyamines,Spermine,Spermidine,Putrescine},
  language     = {eng},
  number       = {4},
  pages        = {501--507},
  publisher    = {Springer},
  series       = {Pflügers Archiv},
  title        = {Effects of polyamines on voltage-activated calcium channels in guinea-pig intestinal smooth muscle},
  url          = {http://dx.doi.org/10.1007/BF00373886},
  volume       = {430},
  year         = {1995},
}