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Free cytosolic calcium during spontaneous contractions in smooth muscle of the guinea-pig mesotubarium

Himpens, B; Lydrup, M L; Hellstrand, Per LU and Casteels, R (1990) In Pflügers Archiv 417(4). p.404-409
Abstract
The free intracellular calcium ion concentration ([Ca2+]i) was measured simultaneously with isometric force in strips of guinea-pig mesotubarium using the Fura-2 technique. During the relaxed period (5-15 min) between spontaneous contractions [Ca2+]i continues to decrease after full mechanical relaxation to reach a minimal level of 86 +/- 8 nM (n = 9) just before the start of the next contraction. During the spontaneous contractions (5-15 min) [Ca2+]i reached a maximum of 211 +/- 19 nM and then oscillated between 155 +/- 16 nM and 194 +/- 9 nM. Increased extracellular Ca2+ concentration to 10 mM from the standard concentration of 1.5 mM caused a decreased frequency of spontaneous contractions and an increase in [Ca2+]i both in the relaxed... (More)
The free intracellular calcium ion concentration ([Ca2+]i) was measured simultaneously with isometric force in strips of guinea-pig mesotubarium using the Fura-2 technique. During the relaxed period (5-15 min) between spontaneous contractions [Ca2+]i continues to decrease after full mechanical relaxation to reach a minimal level of 86 +/- 8 nM (n = 9) just before the start of the next contraction. During the spontaneous contractions (5-15 min) [Ca2+]i reached a maximum of 211 +/- 19 nM and then oscillated between 155 +/- 16 nM and 194 +/- 9 nM. Increased extracellular Ca2+ concentration to 10 mM from the standard concentration of 1.5 mM caused a decreased frequency of spontaneous contractions and an increase in [Ca2+]i both in the relaxed and contracted states. In 10 mM extracellular Ca2+, addition of AlF4-, as 1 mM NaF + 10 microM AlCl3, caused a sustained increase in [Ca2+]i and maintained force. Addition of verapamil (10 microM) in this situation decreased [Ca2+]i to the resting level. The results suggest that the cyclic appearance of trains of action potentials is related to variation in [Ca2+]i, possibly via inactivation of Ca2(+)-dependent K+ channels. (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
[Ca2+]i, Smooth muscle, Mesotubarium, Pacemaker activity
in
Pflügers Archiv
volume
417
issue
4
pages
404 - 409
publisher
Springer
external identifiers
  • pmid:2080105
  • scopus:0025610677
ISSN
0031-6768
DOI
10.1007/BF00370660
language
English
LU publication?
yes
id
7494aee9-6fb3-447c-91cf-2f628259d995 (old id 1105281)
date added to LUP
2008-08-05 12:11:28
date last changed
2017-08-27 05:29:56
@article{7494aee9-6fb3-447c-91cf-2f628259d995,
  abstract     = {The free intracellular calcium ion concentration ([Ca2+]i) was measured simultaneously with isometric force in strips of guinea-pig mesotubarium using the Fura-2 technique. During the relaxed period (5-15 min) between spontaneous contractions [Ca2+]i continues to decrease after full mechanical relaxation to reach a minimal level of 86 +/- 8 nM (n = 9) just before the start of the next contraction. During the spontaneous contractions (5-15 min) [Ca2+]i reached a maximum of 211 +/- 19 nM and then oscillated between 155 +/- 16 nM and 194 +/- 9 nM. Increased extracellular Ca2+ concentration to 10 mM from the standard concentration of 1.5 mM caused a decreased frequency of spontaneous contractions and an increase in [Ca2+]i both in the relaxed and contracted states. In 10 mM extracellular Ca2+, addition of AlF4-, as 1 mM NaF + 10 microM AlCl3, caused a sustained increase in [Ca2+]i and maintained force. Addition of verapamil (10 microM) in this situation decreased [Ca2+]i to the resting level. The results suggest that the cyclic appearance of trains of action potentials is related to variation in [Ca2+]i, possibly via inactivation of Ca2(+)-dependent K+ channels.},
  author       = {Himpens, B and Lydrup, M L and Hellstrand, Per and Casteels, R},
  issn         = {0031-6768},
  keyword      = {[Ca2+]i,Smooth muscle,Mesotubarium,Pacemaker activity},
  language     = {eng},
  number       = {4},
  pages        = {404--409},
  publisher    = {Springer},
  series       = {Pflügers Archiv},
  title        = {Free cytosolic calcium during spontaneous contractions in smooth muscle of the guinea-pig mesotubarium},
  url          = {http://dx.doi.org/10.1007/BF00370660},
  volume       = {417},
  year         = {1990},
}