Subject(s)
Coronary Disease/physiopathology , Animals , Anura , Epinephrine/pharmacology , Membrane Potentials/drug effects , RatsABSTRACT
The use of a technique of in vivo microspectrophotometry with ultraviolet polarized light on frog myocardial trabeculae or isolated fibers has indicated an increase in the fraction of oriented aromatic aminoacids and a decrease in the fraction of bounded nucleotides, during the contractile event.
Subject(s)
Muscle Contraction , Muscles/metabolism , Adenosine Triphosphate , Animals , Muscle Proteins , Myocardium , Protein Conformation , Spectrophotometry, Ultraviolet , Spectrum Analysis , Tryptophan , TyrosineSubject(s)
Heart/physiology , Muscles/physiology , Animals , Birefringence , Circular Dichroism , Fluorescence , Light , Muscle Contraction , Myocardial Contraction , Rana esculenta , Scattering, Radiation , Spectrophotometry , SucroseABSTRACT
The contractile activity,measured on a small portion of myocardial trabeculae or skeletal muscle, is accompanied by optical changes, analyzed using a signal averaging technique. Scattering changes correspond mainly to structural modifications (volume); absorption changes are attributed to early metabolic events while birefringence changes are related to variations in mechanical tension.
Subject(s)
Heart/physiology , Muscles/physiology , Animals , Birefringence , Circular Dichroism , Electric Stimulation , Light , Muscle Contraction , Myocardial Contraction , Rana esculenta , Scattering, Radiation , SpectrophotometryABSTRACT
The optical properties of myocardial fibers and skeletal fibers were compared at rest and during activity. Scattering by myocardial trabeculae is more important than by skeletal fibers but birefringence of myocardial trabeculae is less important than that of skeletal fibers. The absorbance curves of both isolated myocardial trabeculae and skeletal fibers in vivo reflect their main components; during contraction the absorbance increases mainly at 285 nm and this increase starts earlier than contraction recorded with a mechanotransducer. An absorbance change in the spectral range of 420-440 nm is also reported which could represent very early biochemical change in the contractile fibers. The technique used, combined with electrophysiological data, allows one to study different problems related to the biophysics and biochemistry of contraction.
Subject(s)
Muscle Contraction , Myocardial Contraction , Animals , Anura , Birefringence , Fluorescence , Light , Rana esculenta , Scattering, Radiation , Spectrum AnalysisABSTRACT
The main components of the excitable membranes are protein and lipoproteins absorbing in the ultraviolet. Contractile proteins in muscle also absorb ultraviolet light. If polarized light is used, it becomes possible to distinguish the orientation of the absorbing groups either at rest or during activity. A system of microspectrophotometry in vivo using polarized ultraviolet light has been established to study the portion of myocardial trabeculae or of skeletal fibers in the central compartment of a double sucrose gap apparatus. Thus the system also allows electrophysiological studies. On both preparations, a relation between the absorbance change at 280 nm and contractile activity has been measured. These preparations also contain a fraction of oriented compounds absorbing at 280 nm and another at 260 nm. During mechanical activity, the amount of oriented compounds increases at 280 nm and decreases at 260 nm. These changes were assigned to an increase in the ratio of oriented amino acids, tyrosine and tryptophan, and to a decrease of oriented adenosine triphosphate.
