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Endogenous polyamines modulate Ca2+ channel activity in guinea-pig intestinal smooth muscle

Gomez, Maria LU and Hellstrand, Per LU (1999) In Pflügers Archiv 438(4). p.445-451
Abstract
The polyamines spermine and spermidine inhibit L-type Ca2+ channels in whole-cell recordings from guinea-pig ileum cells (Gomez and Hellstrand, Pflugers Arch, 430:501-507, 1995 [4]). To study whether they modulate channel activity under physiological conditions, we further investigated their actions on Ca2+ channels and the effects of altered cellular polyamine contents. In inside-out patches, spermine (0.1-1 mM) inhibited channel activity without affecting the amplitude of unitary currents. In cell-attached recordings, addition of spermine to the bath did not influence channel activity in the patch, indicating that its extracellular action is direct and not mediated via passage of the polyamine through the cell membrane. Cellular contents... (More)
The polyamines spermine and spermidine inhibit L-type Ca2+ channels in whole-cell recordings from guinea-pig ileum cells (Gomez and Hellstrand, Pflugers Arch, 430:501-507, 1995 [4]). To study whether they modulate channel activity under physiological conditions, we further investigated their actions on Ca2+ channels and the effects of altered cellular polyamine contents. In inside-out patches, spermine (0.1-1 mM) inhibited channel activity without affecting the amplitude of unitary currents. In cell-attached recordings, addition of spermine to the bath did not influence channel activity in the patch, indicating that its extracellular action is direct and not mediated via passage of the polyamine through the cell membrane. Cellular contents of spermidine and spermine were decreased by about 50% by organ culture of ileum strips for 5 days with the adenosylmethionine decarboxylase inhibitor CGP 48664 (10 microM). This caused enhanced channel activity in cell-attached recordings, suggesting a reduced level of channel block by endogenous polyamines compared with control cells. Whole-cell recordings in the perforated patch mode showed increased current in polyamine-depleted cells, while this was not seen when cells were dialysed with the pipette solution. We conclude that polyamines block Ca2+ channels from the inside as well as the outside of the cell membrane, and that endogenous polyamines in smooth muscle modulate Ca2+ channel activity. (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
Polyamine, Smooth muscle, Calcium channels
in
Pflügers Archiv
volume
438
issue
4
pages
445 - 451
publisher
Springer
external identifiers
  • pmid:10519136
  • scopus:0032862424
ISSN
0031-6768
DOI
10.1007/s004249900068
language
English
LU publication?
yes
id
c0f810e4-7cca-4d09-929a-5516faf3049d (old id 1114327)
date added to LUP
2008-07-03 16:42:16
date last changed
2017-01-01 07:20:26
@article{c0f810e4-7cca-4d09-929a-5516faf3049d,
  abstract     = {The polyamines spermine and spermidine inhibit L-type Ca2+ channels in whole-cell recordings from guinea-pig ileum cells (Gomez and Hellstrand, Pflugers Arch, 430:501-507, 1995 [4]). To study whether they modulate channel activity under physiological conditions, we further investigated their actions on Ca2+ channels and the effects of altered cellular polyamine contents. In inside-out patches, spermine (0.1-1 mM) inhibited channel activity without affecting the amplitude of unitary currents. In cell-attached recordings, addition of spermine to the bath did not influence channel activity in the patch, indicating that its extracellular action is direct and not mediated via passage of the polyamine through the cell membrane. Cellular contents of spermidine and spermine were decreased by about 50% by organ culture of ileum strips for 5 days with the adenosylmethionine decarboxylase inhibitor CGP 48664 (10 microM). This caused enhanced channel activity in cell-attached recordings, suggesting a reduced level of channel block by endogenous polyamines compared with control cells. Whole-cell recordings in the perforated patch mode showed increased current in polyamine-depleted cells, while this was not seen when cells were dialysed with the pipette solution. We conclude that polyamines block Ca2+ channels from the inside as well as the outside of the cell membrane, and that endogenous polyamines in smooth muscle modulate Ca2+ channel activity.},
  author       = {Gomez, Maria and Hellstrand, Per},
  issn         = {0031-6768},
  keyword      = {Polyamine,Smooth muscle,Calcium channels},
  language     = {eng},
  number       = {4},
  pages        = {445--451},
  publisher    = {Springer},
  series       = {Pflügers Archiv},
  title        = {Endogenous polyamines modulate Ca2+ channel activity in guinea-pig intestinal smooth muscle},
  url          = {http://dx.doi.org/10.1007/s004249900068},
  volume       = {438},
  year         = {1999},
}