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Contractile and metabolic characteristics of creatine-depleted vascular smooth muscle of the rat portal vein

Ekmehag, Björn LU and Hellstrand, Per LU (1988) In Acta Physiologica Scandinavica 133(4). p.525-533
Abstract
The functional consequences of phosphocreatine (PCr) depletion for mechanical properties, O2 consumption, and lactate production of the rat portal vein were investigated. After feeding rats for 8-9 weeks on a diet containing 2% beta-guanidino propionic acid (BGPA), PCr of the portal vein was reduced to 14% of control, whereas ATP was unchanged. No significant change was found in the level of spontaneous contractile activity or the force developed in a high-K+ contracture. Lactate production and the relationship between contractile force and O2 consumption were uninfluenced by BGPA treatment. The force-velocity relation of electrically stimulated portal veins showed no influence of BGPA treatment on Vmax. To investigate whether decrease in... (More)
The functional consequences of phosphocreatine (PCr) depletion for mechanical properties, O2 consumption, and lactate production of the rat portal vein were investigated. After feeding rats for 8-9 weeks on a diet containing 2% beta-guanidino propionic acid (BGPA), PCr of the portal vein was reduced to 14% of control, whereas ATP was unchanged. No significant change was found in the level of spontaneous contractile activity or the force developed in a high-K+ contracture. Lactate production and the relationship between contractile force and O2 consumption were uninfluenced by BGPA treatment. The force-velocity relation of electrically stimulated portal veins showed no influence of BGPA treatment on Vmax. To investigate whether decrease in PCr influenced the response to metabolic stress, portal veins were exposed to graded concentrations (0.1-0.5 mM) of cyanide to depress cellular respiration. Veins from control and BGPA-treated rats showed the same relative decrease of contractile activity and O2 consumption, and the same increase in lactate production. Cyanide treatment resulting in a reduction of electrically stimulated force to 70-80% of the original gave a reduction of Vmax to 85-90%. The relative degree of reduction was uninfluenced by BGPA treatment. Reduction of PCr content thus does not affect the functional properties of metabolism or contractility under normoxic conditions. Furthermore, it can be inferred that the PCr reduction known to occur in smooth muscle exposed to hypoxia (Lovgren & Hellstrand 1985) is not in itself the major factor causing hypoxic inhibition of mechanical activity. (Less)
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author
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Contribution to journal
publication status
published
subject
in
Acta Physiologica Scandinavica
volume
133
issue
4
pages
525 - 533
publisher
Wiley-Blackwell
external identifiers
  • pmid:3227937
  • scopus:0023785191
ISSN
0001-6772
language
English
LU publication?
yes
id
4fd8b419-7229-4a78-9871-11402ff7ccea (old id 1104243)
date added to LUP
2008-08-07 13:09:36
date last changed
2017-01-01 07:24:42
@article{4fd8b419-7229-4a78-9871-11402ff7ccea,
  abstract     = {The functional consequences of phosphocreatine (PCr) depletion for mechanical properties, O2 consumption, and lactate production of the rat portal vein were investigated. After feeding rats for 8-9 weeks on a diet containing 2% beta-guanidino propionic acid (BGPA), PCr of the portal vein was reduced to 14% of control, whereas ATP was unchanged. No significant change was found in the level of spontaneous contractile activity or the force developed in a high-K+ contracture. Lactate production and the relationship between contractile force and O2 consumption were uninfluenced by BGPA treatment. The force-velocity relation of electrically stimulated portal veins showed no influence of BGPA treatment on Vmax. To investigate whether decrease in PCr influenced the response to metabolic stress, portal veins were exposed to graded concentrations (0.1-0.5 mM) of cyanide to depress cellular respiration. Veins from control and BGPA-treated rats showed the same relative decrease of contractile activity and O2 consumption, and the same increase in lactate production. Cyanide treatment resulting in a reduction of electrically stimulated force to 70-80% of the original gave a reduction of Vmax to 85-90%. The relative degree of reduction was uninfluenced by BGPA treatment. Reduction of PCr content thus does not affect the functional properties of metabolism or contractility under normoxic conditions. Furthermore, it can be inferred that the PCr reduction known to occur in smooth muscle exposed to hypoxia (Lovgren & Hellstrand 1985) is not in itself the major factor causing hypoxic inhibition of mechanical activity.},
  author       = {Ekmehag, Björn and Hellstrand, Per},
  issn         = {0001-6772},
  language     = {eng},
  number       = {4},
  pages        = {525--533},
  publisher    = {Wiley-Blackwell},
  series       = {Acta Physiologica Scandinavica},
  title        = {Contractile and metabolic characteristics of creatine-depleted vascular smooth muscle of the rat portal vein},
  volume       = {133},
  year         = {1988},
}