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Polyamines increase Ca2+ sensitivity in permeabilized smooth muscle of guinea pig ileum

Swärd, Karl LU ; Nilsson, Bengt-Olof LU and Hellstrand, Per LU (1994) In American Journal of Physiology 266(6). p.1754-1763
Abstract
The effects of polyamines were investigated in strips of smooth muscle from guinea pig ileum permeabilized with beta-escin (0.005%). Spermine (1 mM) inhibited transient contractions induced in Ca(2+)-free medium by carbachol (0.1 mM) and GTP gamma S (0.1 mM) but potentiated responses to caffeine (20 mM) and D-myo-inositol 1,4,5-trisphosphate (40 microM). At high ethylene glycol-bis(beta-amino-ethyl ether)-N,N,N',N'-tetraacetic acid concentration (10 mM) and in the presence of A-23187 (10 microM), force at optimal and suboptimal Ca2+ concentrations was increased both by spermine and by carbachol. Spermine did not potentiate contraction in Ca(2+)-free medium or after full thiophosphorylation of the regulatory 20-kDa myosin light chains but... (More)
The effects of polyamines were investigated in strips of smooth muscle from guinea pig ileum permeabilized with beta-escin (0.005%). Spermine (1 mM) inhibited transient contractions induced in Ca(2+)-free medium by carbachol (0.1 mM) and GTP gamma S (0.1 mM) but potentiated responses to caffeine (20 mM) and D-myo-inositol 1,4,5-trisphosphate (40 microM). At high ethylene glycol-bis(beta-amino-ethyl ether)-N,N,N',N'-tetraacetic acid concentration (10 mM) and in the presence of A-23187 (10 microM), force at optimal and suboptimal Ca2+ concentrations was increased both by spermine and by carbachol. Spermine did not potentiate contraction in Ca(2+)-free medium or after full thiophosphorylation of the regulatory 20-kDa myosin light chains but slightly potentiated contractions produced by partial thiophosphorylation. Also, spermidine and putrescine, as well as the aminoglycoside antibiotic neomycin, increased sensitivity to Ca2+, with potency correlating with number of positive charges. After permeabilization by a high concentration (0.1%) of beta-escin, the sensitivity to Ca2+ was increased by spermine but not by GTP gamma S. In preparations permeabilized by Triton X-100, spermine slightly increased Ca2+ sensitivity but not maximal force. Tissue contents of putrescine, spermidine, and spermine in intact ileum muscle were 8, 98, and 184 nmol/g, respectively. Permeabilization by 0.005 and 0.1% beta-escin reduced spermine contents by 40 and 53%, respectively. Effects of added polyamines in permeabilized preparations may thus reflect physiological effects of endogenous polyamines modulating contraction in the intact tissue. (Less)
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Contribution to journal
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published
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in
American Journal of Physiology
volume
266
issue
6
pages
1754 - 1763
publisher
American Pysiological Society
external identifiers
  • pmid:8023905
ISSN
0002-9513
language
English
LU publication?
yes
id
868934b5-996f-40fa-9886-6eb219b21d75 (old id 1107894)
alternative location
http://ajpcell.physiology.org/cgi/reprint/266/6/C1754
date added to LUP
2008-07-23 09:31:39
date last changed
2016-04-16 02:56:32
@article{868934b5-996f-40fa-9886-6eb219b21d75,
  abstract     = {The effects of polyamines were investigated in strips of smooth muscle from guinea pig ileum permeabilized with beta-escin (0.005%). Spermine (1 mM) inhibited transient contractions induced in Ca(2+)-free medium by carbachol (0.1 mM) and GTP gamma S (0.1 mM) but potentiated responses to caffeine (20 mM) and D-myo-inositol 1,4,5-trisphosphate (40 microM). At high ethylene glycol-bis(beta-amino-ethyl ether)-N,N,N',N'-tetraacetic acid concentration (10 mM) and in the presence of A-23187 (10 microM), force at optimal and suboptimal Ca2+ concentrations was increased both by spermine and by carbachol. Spermine did not potentiate contraction in Ca(2+)-free medium or after full thiophosphorylation of the regulatory 20-kDa myosin light chains but slightly potentiated contractions produced by partial thiophosphorylation. Also, spermidine and putrescine, as well as the aminoglycoside antibiotic neomycin, increased sensitivity to Ca2+, with potency correlating with number of positive charges. After permeabilization by a high concentration (0.1%) of beta-escin, the sensitivity to Ca2+ was increased by spermine but not by GTP gamma S. In preparations permeabilized by Triton X-100, spermine slightly increased Ca2+ sensitivity but not maximal force. Tissue contents of putrescine, spermidine, and spermine in intact ileum muscle were 8, 98, and 184 nmol/g, respectively. Permeabilization by 0.005 and 0.1% beta-escin reduced spermine contents by 40 and 53%, respectively. Effects of added polyamines in permeabilized preparations may thus reflect physiological effects of endogenous polyamines modulating contraction in the intact tissue.},
  author       = {Swärd, Karl and Nilsson, Bengt-Olof and Hellstrand, Per},
  issn         = {0002-9513},
  language     = {eng},
  number       = {6},
  pages        = {1754--1763},
  publisher    = {American Pysiological Society},
  series       = {American Journal of Physiology},
  title        = {Polyamines increase Ca2+ sensitivity in permeabilized smooth muscle of guinea pig ileum},
  volume       = {266},
  year         = {1994},
}