Permeability characteristics of muscle membrane
Biochimica Et Biophysica Acta
|August 14, 1980
Summary
This study measured the transport of fatty acids across rat diaphragm membranes. Findings suggest cell membranes share structural similarities across species and tissues, with small molecules potentially using aqueous pores.
Area of Science:
- Biochemistry
- Cell Biology
- Physiology
Background:
- Cell membrane permeability is crucial for understanding molecular transport.
- Fatty acids, alcohols, and bile acids are key biological molecules with varying lipophilicity.
- Rat diaphragm provides an intact tissue model for studying membrane transport.
Purpose of the Study:
- To quantify unidirectional flux rates of saturated fatty acids, alcohols, and bile acids in a rat diaphragm.
- To investigate the relationship between fatty acid chain length and membrane permeability.
- To infer properties of the muscle cell membrane based on transport data.
Main Methods:
- Utilized an intact rat diaphragm preparation for flux measurements.
- Measured unidirectional flux rates of various lipid molecules.
- Analyzed permeability coefficients in relation to molecular structure (carbon chain length).
Main Results:
- Permeability coefficients for fatty acids (5-10 carbons) showed a linear relationship with carbon number.
- Calculated incremental free energies of solution for hydroxyl and methylene groups.
- Observed unexpectedly high permeability for short-chain fatty acids (<5 carbons) in muscle membranes.
Conclusions:
- Muscle cell membranes exhibit structural similarities to other tissues and species.
- Short-chain fatty acids may traverse membranes via polar regions or aqueous pores, as muscle lacks tight junctions.
- The findings contribute to understanding lipid transport mechanisms across biological membranes.
Related Concept Videos
01:16Introduction to Membrane Proteins
The cell membrane, or plasma membrane, is an ever-changing landscape. It is described as a fluid mosaic where various macromolecules are embedded in the phospholipid bilayer. Among the macromolecules are proteins. The protein content varies across cell types. For example, mitochondrial inner membranes contain ~76% protein content, while myelin contains ~18% protein content. Individual cells contain many types of membrane proteins—red blood cells contain over 50—and different cell types have...
01:15Overview of Skeletal Muscle
Skeletal muscles are composed of a bundle of muscle fibers and are attached to bones through tendons. Each skeletal muscle fiber is a single muscle cell. The sarcolemma, the plasma membrane of a skeletal muscle cell, consists of a lipid bilayer and glycocalyx that supports muscle fibers. The sarcolemma extends into the muscle cells to form tubular structures called transverse or T-tubules. Each side of the T-tubules consists of a membrane-bound structure called the sarcoplasmic reticulum,...
01:25Overview of Muscle Tissues
The human body has three types of muscle tissue: skeletal, smooth, and cardiac. Each class has unique properties that enable them to perform specific functions. However, all muscle tissues share certain properties, including elasticity, contractility, and excitability.
Elasticity
Elasticity is the ability of muscles to stretch and return to their original shape. This property is partly due to elastic fibers — macromolecules that run through the muscles. These fibers are firm and resilient,...
Elasticity
Elasticity is the ability of muscles to stretch and return to their original shape. This property is partly due to elastic fibers — macromolecules that run through the muscles. These fibers are firm and resilient,...
01:13Microscopic Anatomy of Skeletal Muscles
Skeletal muscle cells, also called muscle fibers, are distinctly elongated, multi-nucleated, slender biological units. They are packed with specialized structures designed to facilitate their primary function, which is contraction.
The muscle sarcolemma is a plasma membrane enclosing each muscle cell that conducts electrical signals called action potentials. The sarcolemma extends into the cell to form T-tubules, ensuring the neural impulses are uniformly distributed across the entire muscle...
The muscle sarcolemma is a plasma membrane enclosing each muscle cell that conducts electrical signals called action potentials. The sarcolemma extends into the cell to form T-tubules, ensuring the neural impulses are uniformly distributed across the entire muscle...
01:24Generation of Action Potential in Skeletal Muscles
Every cell in the body maintains a membrane potential due to an uneven distribution of positive and negative charges across its plasma membrane. The membrane potential is measured in millivolts and quantifies the difference in charge across the membrane.
Like neurons, muscle cells are also regarded as excitable due to their capacity to change in response to stimuli, primarily due to voltage-gated ion channels embedded in their plasma membranes, which get activated by alterations in the cell's...
Like neurons, muscle cells are also regarded as excitable due to their capacity to change in response to stimuli, primarily due to voltage-gated ion channels embedded in their plasma membranes, which get activated by alterations in the cell's...
01:27Specialized Characteristics of Cardiac Muscles
The primary role of cardiac muscles is to propel blood throughout the cardiovascular system. The cardiac muscle cells, or cardiomyocytes, exhibit specialized characteristics that allow them to perform this function.
Cardiac muscle cells are smaller than skeletal muscles, averaging 10–20 mm in diameter and 50–100 mm in length. However, they have large energy demands for continuous contraction and relaxation. This energy is almost exclusively derived from aerobic metabolism of energy reserves in...
Cardiac muscle cells are smaller than skeletal muscles, averaging 10–20 mm in diameter and 50–100 mm in length. However, they have large energy demands for continuous contraction and relaxation. This energy is almost exclusively derived from aerobic metabolism of energy reserves in...