Skeletal Muscle Carnosine Research Articles

Influence of β-alanine supplementation on skeletal muscle carnosine concentrations and high intensity cycling capacity

Muscle carnosine synthesis is limited by the availability of beta-alanine. Thirteen male subjects were supplemented with beta-alanine (CarnoSyn) for 4 wks, 8 of these for 10 wks. A biopsy of the vastus lateralis was obtained from 6 of the 8 at 0, 4 and 10 wks. Subjects undertook a cycle capacity test to determine total work done (TWD) at 110% (CCT(110%)) of their maximum power (Wmax). Twelve matched subjects received a placebo. Eleven of these completed the CCT(110%) at 0 and 4 wks, and 8, 10 wks. Muscle biopsies were obtained from 5 of the 8 and one additional subject. Muscle carnosine was significantly increased by +58.8% and +80.1% after 4 and 10 wks beta-alanine supplementation. Carnosine, initially 1.71 times higher in type IIa fibres, increased equally in both type I and IIa fibres. No increase was seen in control subjects. Taurine was unchanged by 10 wks of supplementation. 4 wks beta-alanine supplementation resulted in a significant increase in TWD (+13.0%); with a further +3.2% increase at 10 wks. TWD was unchanged at 4 and 10 wks in the control subjects. The increase in TWD with supplementation followed the increase in muscle carnosine.

The Effect of Sprint Training on Skeletal Muscle Carnosine in Humans

It has been suggested that histidine-containing dipeptide carnosine (β-alanyl-L-histidine), which is believed to act as a cytosolic buffering agent, is present predominantly in skeletal muscle. The purpose of this study was to investigate the effects of sprint training (30-s maximal cycle ergometer sprinting) on muscle carnosine concentration. Six untrained males trained 2 days per week for 8 weeks on an electronic-braked cycle ergometer. Muscle biopsy samples were taken from the vastus lateralis before and two days after the last training session and were analyzed for carnosine concentration by the use of an amino acid autoanalyzer. The carnosine concentration was significantly increased after sprint training (P < 0.05). The mean power during 30-s maximal cycle ergometer sprinting was significantly increased following training. When dividing the 30-s sprinting into 6 phases (0-5, 6-10, 11-15, 16-20, 21-25, 26-30 s), the magnitude of increase in mean power was significantly larger for the last 2 phases than the first phase (P < 0.05). These results suggest that the increases in skeletal muscle carnosine concentration following sprint training may be associated with the increase in sustainability of high power during 30-s maximal cycle ergometer sprinting.

Gender-related differences in carnosine, anserine and lysine content of murine skeletal muscle

The aminoacyl-imidazole dipeptides carnosine (beta-alanyl-L-histidine) and anserine (beta-alanyl-1-methyl-histidine) are present in relatively high concentrations in excitable tissues, such as muscle and nervous tissue. In the present study we describe the existence of a marked sexual dimorphism of carnosine and anserine in skeletal muscles of CD1 mice. In adult animals the concentrations of anserine were higher than those of carnosine in all skeletal muscles studied, and the content of aminoacyl-imidazole dipeptides was remarkably higher in males than in females. Postnatal ontogenic studies and hormonal manipulations indicated that carnosine synthesis was up-regulated by testosterone whereas anserine synthesis increased with age. Regional variations in the concentrations of the dipeptides were observed in both sexes, skeletal muscles from hind legs having higher amounts of carnosine and anserine than those present in fore legs or in the pectoral region. The concentration of L-lysine in skeletal muscles also showed regional variations and a sexual dimorphic pattern with females having higher levels than males in all muscles studied. The results suggest that these differences may be related with the anabolic action of androgens on skeletal muscle.

Plasma carnosine concentration: diurnal variation and effects of age, exercise and muscle damage.

This study was undertaken as part of a larger investigation into carnosine metabolism and function in the Thoroughbred horse. More specifically, we wished to evaluate plasma carnosine concentration as a potential indicator of muscle carnosine status. In contrast to man, carnosine is present in equine plasma where its presence is consistent with the absence of plasma carnosinase. A significant effect of age on plasma carnosine concentration in resting Thoroughbred horses was observed. Values in horses age 3 years and older were 113-14.1 micromol/l, whereas concentrations in foals and yearlings were 3.9-8.7 micromol/l (P<0.001). Lower values in young horses may reflect lower skeletal muscle carnosine concentrations. There was no significant within-day variation in plasma carnosine concentration in fed and fasted horses (P>0.05). Intense exercise resulted in a small significant increase (P<0.05) in plasma carnosine concentration (pre-exercise, 10.3 +/- 1.0 micromol/l; postexercise, 12.4 +/- 4.4 micromol/l). Greater increases were observed (57.6-702.3 micromol/l) following onset of exercise-induced rhadomyolysis (ERS). An apparent relationship was observed between elevated plasma carnosine and increased plasma creatine kinase (CK) and aspartate transaminase (AST) activities. Plasma carnosine concentrations did not reflect the severity of the condition as determined by clinical examination. In conclusion, elevated plasma carnosine levels are observed following exercise induced muscle damage, with the greatest elevations occurring during episodes of external rhabdomylosis syndrome. Plasma carnosine measurements could provide an alternative clinical indicator of muscle damage; and in conjunction with plasma taurine measurements may be indicative of selective type 1 or type 2 muscle fibre damage. However, given the complexity of the analytical technique, its applications would probably be confined to specialist referral or research centres.

High Level of Skeletal Muscle Carnosine Contributes to the Latter Half of Exercise Performance during 30-s Maximal Cycle Ergometer Sprinting.

The histidine-containing dipeptide carnosine (beta-alanyl-L-histidine) has been shown to significantly contribute to the physicochemical buffering in skeletal muscles, which maintains acid-base balance when a large quantity of H(+) is produced in association with lactic acid accumulation during high-intensity exercise. The purpose of the present study was to examine the relations among the skeletal muscle carnosine concentration, fiber-type distribution, and high-intensity exercise performance. The subjects were 11 healthy men. Muscle biopsy samples were taken from the vastus lateralis at rest. The carnosine concentration was determined by the use of an amino acid autoanalyzer. The fiber-type distribution was determined by the staining intensity of myosin adenosinetriphosphatase. The high-intensity exercise performance was assessed by the use of 30-s maximal cycle ergometer sprinting. A significant correlation was demonstrated between the carnosine concentration and the type IIX fiber composition (r=0.646, p<0.05). The carnosine concentration was significantly correlated with the mean power per body mass (r=0.785, p<0.01) during the 30-s sprinting. When dividing the sprinting into 6 phases (0-5, 6-10, 11-15, 16-20, 21-25, 26-30 s), significant correlations were observed between the carnosine concentration and the mean power per body mass of the final 2 phases (21-25 s: r=0.694, p<0.05; 26-30 s: r=0.660, p<0.05). These results indicated that the carnosine concentration could be an important factor in determining the high-intensity exercise performance.

SKELETAL MUSCLE CARNOSINE LEVEL MAY CONTRIBUTE TO SUPERIOR PERFORMANCE DURING HIGH INTENSITY EXERCISE

Dipeptide carnosine (β-alanyl-L-histidine) has been shown to contribute significantly to physico-chemical buffering in skeletal muscle, which maintains acid-base balance when large quantities of hydrogen ions are produced in association with lactic acid accumulation during high intensity exercise. The purpose of this study was to examine relationships among skeletal muscle carnosine level, fiber type distribution and high intensity exercise performance. The subjects were twenty healthy men. Muscle biopsy samples were taken from the vastus lateralis at rest. Carnosine level were determined using an amino acid AutoAnalyzer. Fiber type distribution was determined by staining intensity of myosin adenosinetriphosphatase. High intensity exercise performance was assessed using 30-s cycle ergometer sprinting. Significant (P < 0.05) interrelationships were demonstrated between carnosine level and type II fiber composition. Superior sprint performance was associated with type II fiber composition and carnosine level. When dividing the 30-s sprinting into 6 phases (0–5, 6–10, 11–15, 16–20, 21–25, 26–30 s), significant correlations were observed between carnosine level and mean power of the latter 3 phases (16–20 s: P < 0.05, 21–25 s: P < 0.01 and 26–30 s: P < 0.05). These results indicate that carnosine level may be an important determinant of high intensity exercise performance.

Detection, characterisation, and quantification of carnosine and other histidyl derivatives in cardiac and skeletal muscle

Isocratic reverse phase analytical high performance liquid chromatography (HPLC) has been used to examine naturally occurring imidazoles of cardiac and skeletal muscles. Elution of muscle extracts with a phosphate buffer mobile phase from columns packed with hypersil ODS (5 μm) resulted in good separation of the skeletal muscle imidazole-containing dipeptides carnosine and anserine. Measured concentrations corresponded to published values. N-Acetyl forms that were not commercially available were prepared from their parent compounds and their identities verified by NMR-spectroscopy. Examination of frog cardiac muscle confirmed the presence of N-acetylhistidine and also indicated the presence of its 1-methyl derivative. Extracts of mammalian cardiac muscle were examined by HPLC which indicated the presence of low concentrations of carnosine but substantial amounts of N-acetyl forms of histidine, 1-methylhistidine, carnosine and anserine. Fractions corresponding to the numerous peaks were examined using staining systems specific for certain chemical features and compared to results obtained for commercial or synthetic standards. Results of these tests supported the chromatographic data. The total concentrations in cardiac muscle of these imidazole-containing substances (approx. 10 mM) is sufficient to alter significantly the sensitivity of their contractile apparatus to calcium ions.

An evaluation of a method to differentiate the species of origin of meats on the basis of the contents of anserine, balenine and carnosine in skeletal muscle

AbstractThe high performance liquid chromatographic method proposed by Carnegie for determining the species of origin of meats in cooked products has been evaluated. The dipeptides anserine, balenine (ophidine) and carnosine have been extracted from the skeletal muscle of animals in New Zealand and compared with results obtained in Australia. The presence of significant quantities of balenine in red deer meat is reported for the first time. Limitations of the method are discussed.

Effects of neuromuscular blockers on carnosine levels in rat skeletal muscle.

A 30-min treatment with neuromuscular blocking doses of either physostigmine or d-tubocurarine was associated with a 44% or 36% (respectively) reduction in rat skeletal muscle carnosine levels in vivo.

Spectrophotometric determination of carnosine, anserine, and taurine in skeletal muscle

The determination of carnosine using the diazonium salt of p-bromoaniline and the determination of taurine and of taurine, carnosine, and anserine together using 2,4-dinitro-1-fluorobenzene to give yellow-colored derivatives is the basis for the spectrophotometric assay of these compounds in skeletal muscle. The procedure can be applied directly to aqueous extracts of muscle and is well suited for routine assays of many samples.

Factors affecting anserine and carnosine levels in skeletal muscles of various animals

1. 1. Analytical procedures for anserine, carnosine and related histidine compounds in skeletal muscles are given. 2. 2. The anserine/carnosine ratio in the skeletal muscles of the rat increases with age, cortisone injection and lowered food intake, and in the guinea pig muscle with strenuous exercise. 3. 3. The total anserine plus carnosine in leg muscles of the cat remain constant during long periods of deep anesthesia. 4. 4. Skeletal muscles of man contain carnosine but no anserine. Higher levels of carnosine and low levels of anserine are found in muscles of monkey (Rhesus). 5. 5. Carnosine but no anserine is present in leg muscles of frog.

Muscle metabolism during isometric exercise performed at constant force.

Muscle metabolism during isometric exercise performed at constant force.

Intracellular Distribution of Carnosine and Anserine in Skeletal Muscle

The experiments of Bach and Langley (1) with frog muscle suspensions indicated that the carnosine of this tissue was freely diffusible upon dialysis of homogenates. On the other hand, Reddy and Hegsted (2) observed that the “debris” of rat skeletal muscle homogenates contained 43% of the total carnosine. This debris, representing material sedimented at 650 x g, still retained half of its initial carnosine content after extraction for 7 days in 50% glycerol at -10”. Mitochondria were found to contain over 7% of the total muscle carnosine, and this dipeptide was not removed by suspension of the granules in isotonic sucrose. Reddy and Hegsted concluded that bound carnosine was present within the muscle cell, although it was not clear whether the peptide was attached to myofibrils or whether the microsomes retained any of the carnosine. No results were reported for anserine, the more abundant of the two muscle dipeptides. Inasmuch as a selective binding of carnosine to subcellular components of muscle might offer a clue to the physiological role of this enigmatic peptide, it seemed desirable to further study the intracellular distribution of carnosine, and of anserine as well, in skeletal muscle tissue. We have not been able to confirm the conclusions of Reddy and Hegsted that relatively large concentrations of carnosine are associated with subcellular fractions of rat gastrocnemius muscle. However, by employing more sensitive isotopic labeling methods, it has been possible to demonstrate the retention of very small quantities of carnosine and anserine in certain cellular components of chick pectoral muscle. This tissue was chosen because of its unusually high dipeptide content (3). In addition to normal birds, experiments were performed with genetically dyst,rophic chicks.