PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Muscle, Striated”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1975

Extensive and intensive factors determining the performance of striated muscle.

Striated muscle is obviously a versatile tissue, one which has been malleable to selective pressure and has become modified for many specific tasks. The variations which adapt striated muscle to particular functions involve both changes in its structural organization and changes in the chemical nature of its components. Although a number of factors have been identified which contribute to the diversity of muscle performance, it is not yet possible to account adequately for the wide range in muscle performance throughout the animal kingdom. While not a new direction in comparative physiology, developing quantitative explanations for the diversity of muscle performance is still an obvious, remaining task.

Action Potentials↗
PubMed1992

Intracellular free-magnesium levels in vascular smooth muscle and striated muscle cells of the spontaneously hypertensive rat.

In humans with essential hypertension and in spontaneously hypertensive rats (SHR), insulin resistance may be present even in lean individuals. As the basis for this abnormality is unknown, we have used a newly developed fluorophore to measure intracellular free-Mg2+ concentrations in cultured aortic vascular smooth muscle cells and striated muscle cells from SHR and normotensive Wistar Kyoto (WKY) rats. Intracellular free-Mg2+ levels were lower in both striated muscle cells (SHR, 0.423 +/- 0.077 mmol.L-1 v WKY, 0.559 +/- 0.068 mmol.L-1; P less than .001) and vascular smooth muscle cells (SHR, 0.406 +/- 0.067 mmol.L-1 v WKY, 0.625 +/- 0.077 mmol.L-1; P less than .001) from hypertensive animals. This widespread, intrinsic defect in the regulation of intracellular Mg2+ may explain the increased vascular resistance and reduced insulin sensitivity present in hypertension.

Animals↗
PubMed1982

Adenosine and free-flow functional hyperemia in striated muscle.

Striated muscle arteriolar responses to 1.5 min of 1-Hz contraction and/or increased tissue O2 partial pressure (PO2) were observed during exposure of the tissue interstitial space to adenosine deaminase (ADA) to evaluate the role of adenosine (ADO) as a regulator for blood flow. The microvasculature of the hamster cremaster muscle was continuously superfused with a bicarbonate buffer containing 11 micrograms ADA/ml and equilibrated with 5% CO2 and various O2 concentrations. Arterioles (resting diameter less than 30 micrometers) constricted a maximum of 55% when the superfusate gas tension was increased from 0 to 95% O2, but ADA had no effect on this behavior. Arterioles dilated during exercise, but the diameter change was decreased 20-25% during exercise with ADA treatment at both normal and elevated tissue PO2. As ADA had no effect on either the vasodilation to 2-chloroadenosine or resting arteriolar diameter, it was probably specific in its action. Assuming that all extracellular ADO was accessible to ADA and that ADA neutralized most newly formed ADO, we conclude that ADO is one component of a multifactor system mediating short periods of free-flow exercise hyperemia and that the release of ADO is not necessarily dependent on tissue hypoxia.

Adenosine↗
PubMed1975

Geometrical distribution of capillaries in mammalian striated muscle.

Striated muscles of hindlimb, jaw, or tongue in dogs, cats, rabbits, rats, and guinea pigs were perfused under high pressure with Microfil (a silicone elastomer of viscosity 20 cP approx.) to outline the vascular bed. When the material had set, the muscles were fixed in formalin. Exmination of histological sections, strained by a modified Gomori trichrome method, showed capillaries containing Microfil as well as some, unperfused, filled with red cells. From well-perfused bundles the numbers of capillaries surrounding each fiber were counted; in all muscles these ranged from 0 to 9 with mean values betweeen 3.2 and 4.0. This was true of both red and white muscle. The mean number of fibers sharing one capillary ranged from 2.0 to 3.2, the lower value being found when four vessels surrounded a fiber and the higher value when there was only three. The results indicate a continuum of transitional models from a square array of fibers with each capillary between two adjacent fibers to a hexagonal array with capillaries at alternate vertices.

Animals↗
PubMedDate not supplied

The ultrastructure of striated muscle.

Striated muscle is a tissue in which the major cytoplasmic components are spatially arranged to produce directional motion. This orientation is seen at all levels of structure, beginning with the molecular placement of characteristic proteins into 2 dissimilar types of filaments, and proceeding ultimately to the alignment of muscle fibers in the heart or an anatomically defined skeletal muscle. Generation of contractile force is accomplished by the enzymatic interaction of the 2 dissimilar protein filaments, which results ultimately in the utilization of energy (in the form of adenosine triphosphate) and the production of directional motion.

Animals↗
PubMed1984

Voltage-dependent sodium channels in an invertebrate striated muscle.

Striated skeletal muscles from the planktonic arrowworm Sagitta elegans (phylum Chaetognatha) were voltage-clamped. The muscles displayed classical voltage-dependent sodium channels that (i) showed peak transient currents when the membrane was depolarized 90 millivolts from rest, (ii) opened rapidly with peak currents flowing within 0.4 milliseconds at 4 degrees C, (iii) showed voltage-dependent inactivation with 50 percent inactivation at +25 millivolts from rest, and (iv) were blocked by 500 nanomolar tetrodotoxin.

Action Potentials↗
PubMed2001

The innervation and properties of the urethral striated muscle.

The striated muscle forms an outer sleeve around the urethra and occupies about 80% of the wall. In humans more than 60% of the muscle consists of slow, fatigue resistant type I fibres whereas in male greyhounds only about 6% are type I. Most of the remainder (70% of fibres) are type IIa which are classified as fast but can contract for several hours with little decline in amplitude. Stimulation of pudendal but not pelvic nerves produces contraction of the striated muscle and a rapid increase in urethral pressure. Pelvic nerve branches enter the striated muscle sleeve but pass through it to supply the inner layer of smooth muscle. The striated muscles are well suited to maintain contraction necessary for continence.

Animals↗
PubMed2002

Age effects on urethral striated muscle. I. Changes in number and diameter of striated muscle fibers in the ventral urethra.

OBJECTIVE: This study was undertaken to test the null hypothesis that the number of striated muscle fibers in the ventral wall of the female urethra remains constant with increasing age. STUDY DESIGN: The urethra and surrounding tissues from 25 female cadavers, mean age 52 years (+/-SD 18, range 15-80 years), were selected for this study. Each specimen was divided along the midsagittal plane, and a Masson trichrome histologic section was prepared. A systematic count of striated muscle fibers in the ventral wall was then obtained at each decile of urethral length. RESULTS: A decrease in the total number of fibers within the sampled area was found with increasing age. The mean of the total fibers across all urethrae was 17,423 (+/-SD 9,624, range 4,788-35,867). Over the life span, an average of 364 fibers (2%) were lost per year (95% CI 197-531; P <.001). Mean fiber density was 671 (+/- SD 296, range 228-1374) fibers/mm2 and decreased by 13 fibers/mm2 per year (95% CI 8-17; P <.001). The mean lesser fiber diameter was 24 microm and did not change significantly with age ( P =.3). CONCLUSIONS: The number and density of urethral striated muscle fibers decline with age.

Adolescent↗
PubMed2002

Preventing fatigue of fast striated muscles of the pelvic floor and slow striated muscles of the limb by manipulating the on-off time of electric stimulation.

OBJECTIVE: To investigate in vitro the effect of different on-off electrostimulation times on the fatigue of 2 pelvic muscles, the iliococcygeus and pubococcygeus (mainly fast), and the soleus muscle of the limb (mainly slow). DESIGN: Nonrandomized controlled trial and before-after trial. SETTINGS: In vitro study in tissue baths on stabilized preparations of whole striated muscles. ANIMALS: Young healthy female Wistar rats. INTERVENTION: Applied isometric tetanic contractions of various stimulation durations (on-off times) to dissected rat iliococcygeus and pubococcygeus (at 66Hz) and soleus (at 25Hz) muscles. MAIN OUTCOME MEASURE: Muscle fatigue with changing on-off, frequency, and stimulation times. RESULTS: The longer the off time, the less the fatigue. Shortening the stimulation time can minimize fatigue. Optimal combinations are presented to limit fatigue. CONCLUSION: Changing on-off time and stimulation time can be used to make electric stimulation of pelvic muscles more effective.

Animals↗