Mechanics and Ca(2+)-sensitivity of human detrusor muscle bundles studied in vitro
Author
Summary, in English
Mechanical properties of isolated smooth muscle strips from human urinary bladder were investigated in vitro. Bladder tissue was obtained from tumour-free wall regions of bladders from male patients undergoing cystectomy for bladder carcinoma. In intact muscle strips, activated with high-K+ solution, half-maximal force occurred at about 0.9 mM extracellular [Ca2+]. The length-active force relation was determined and the muscle strips were fixed for light and electron microscopy at optimal length for active force (1o). The maximal active force per unit smooth muscle cross-sectional area was 208 +/- 49 mN/mm2, n = 6. Chemically skinned preparations were obtained by treatment with triton X-100. These preparations had a steep [Ca2+]-force relation in the micromolar range which was influenced by calmodulin. The skinned preparations could be maximally activated by irreversible thiophosphorylation of the regulatory light chains. The force-velocity relation was determined in the maximally activated skinned muscle at 22 degrees C at 0.51o. When the muscle was shortened by 10%, force was reduced by 35% whereas the maximal shortening velocity was little affected.
Publishing year
1991
Language
English
Pages
373-380
Publication/Series
Acta Physiologica Scandinavica
Volume
143
Issue
4
Document type
Journal article
Publisher
Wiley-Blackwell
Topic
- Pharmacology and Toxicology
- Urology and Nephrology
- Physiology
- Medicinal Chemistry
Status
Published
Research group
- Vascular Physiology
- Urology
ISBN/ISSN/Other
- ISSN: 0001-6772