PMID: 6978824May 1, 1982Paper

Tension-pCa relation and sarcoplasmic reticulum responses in chemically skinned smooth muscle fibers

Federation Proceedings
M EndoM Iino

Abstract

Properties of bundles of smooth muscle fibers in which the surface membrane has been rendered highly permeable by chemical treatment (saponin) are described. These preparations are termed chemically skinned smooth muscle fiber bundles. Thin bundles were isolated from guinea pig teniae ceci and skinned in a relaxing solution by treatment with 50 micrograms/ml saponin for 20-30 min. Because Ca2+ sensitivity progressively decreased on repeating contractions or on incubating in a relaxing solution, the tension-pCa (-log10 [free Ca2+]) relationship was determined soon after the skinning by a single contraction in which the [free Ca2+] was increased in a stepwise manner. Unlike skinned skeletal muscle fibers, in skinned smooth muscle fiber bundles the tension-pCa relationship was not affected appreciably by the changes in pH from 6.4 to 7.2, in ionic strength from 0.15 to 0.30 M, or in [MgATP] from 0.4 to 8 mM. The saponin-treated smooth muscle fiber bundles retained a functional sarcoplasmic reticulum (SR). Ca can be loaded in the SR if the [free Ca2+] is in the micromolar range and MgATP is present and can be released by an application of caffeine. Mitochondria also appear to be functional in saponin-treated fibers.

Related Concepts

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Blastomycosis

Blastomycosis fungal infections spread through inhaling Blastomyces dermatitidis spores. Discover the latest research on blastomycosis fungal infections here.

Nuclear Pore Complex in ALS/FTD

Alterations in nucleocytoplasmic transport, controlled by the nuclear pore complex, may be involved in the pathomechanism underlying multiple neurodegenerative diseases including Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Here is the latest research on the nuclear pore complex in ALS and FTD.

Applications of Molecular Barcoding

The concept of molecular barcoding is that each original DNA or RNA molecule is attached to a unique sequence barcode. Sequence reads having different barcodes represent different original molecules, while sequence reads having the same barcode are results of PCR duplication from one original molecule. Discover the latest research on molecular barcoding here.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Evolution of Pluripotency

Pluripotency refers to the ability of a cell to develop into three primary germ cell layers of the embryo. This feed focuses on the mechanisms that underlie the evolution of pluripotency. Here is the latest research.

Position Effect Variegation

Position Effect Variagation occurs when a gene is inactivated due to its positioning near heterochromatic regions within a chromosome. Discover the latest research on Position Effect Variagation here.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.

Microbicide

Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections. Here is the latest research on microbicides.