Carnosine and Skeletal Muscles

From the twenties to the seventies muscle mass of a man reduces by 20% and also reduce the strength and endurance, so that the overall reduction in the efficiency of the muscles is close to 40%. During this period, the concentration of carnosine and its antioxidant effect reduces to half of the original value. This reduction in the concentration of carnosine in muscles most likely impacts on reducing muscle mass, strength and endurance.

Active, strong, the so-called fast muscle fibres contain a large amount of carnosine, while weak and atrophic ones contain significantly less carnosine. Russian scientist Severin proved in the 1950s that adding carnosine to the liquid in which they are kept incubated, isolated, overworked muscles caused the entire recovery of muscle energy.

Carnosine is broken down in the body by carnosinase, which is found in most tissues except skeletal muscle, partially explaining why carnosine concentrations are highest in this tissue. Carnosine in human skeletal muscle generally ranges between 5-10 mM wet weight or 15-40 mmol/kg dry weight

The Australian team of doctor McFarland recently demonstrated that carnosine supply increases strength and endurance of tired muscles. It is interesting that carnosine supplementation is directly associated with the ultimate effect on the muscles: the more increasing supply of carnosine is, the higher is its content in the muscle, by which both a strength and endurance significantly increase. The role of carnosine has been scientifically tested in a variety of neuromuscular disorders. The results of these studies recommend carnosine supplementation in these disorders. It is obvious that it is not expected healing of these serious diseases, but oxidative stress caused by them can be reduced, contractility of the muscles can be increased and the strength and endurance can be improved. The muscles of patients with Duchenne muscular dystrophy contain only half the level of carnosine compared to muscles of healthy individuals, so that carnosine supplementation is recommended.

The normal function of skeletal muscle illustrates the importance of the fine balance between oxidant and antioxidant processes. Intense exercise promotes generation of ROS that at low levels serves an important role in normal force production as well as glucose uptake during contraction. Exercise training is associated with improved antioxidant response over time. However, during the prolonged and extreme oxidative stress found in disease states, poor antioxidant response and increased protein carbonylation are associated with muscle wasting. Additionally, more acute events such as tissue ischemia with subsequent reperfusion are associated with increased ROS production, protein carbonylation, and cellular injury. Karnozin Extra fights ROS and protects skeletal muscles from oxidative stress.

Exercise is one of the well-studied modulators of oxidative stress status in skeletal muscle. The effect of exercise on protein carbonylation in muscle depends on the duration, intensity, and type of exercise. After a single episode of intense exercise, the carbonylation of sarcoplasmic reticulum Ca2+-ATPase is increased 80%. The effect of acute exercise is transient, however, and within 1 h, levels of carbonylation are near normal. The effects of exercise on increasing carbonylation were measured in predominantly anaerobic “white” or fast-twitch muscles, but not in red muscles that have more oxidative muscle fibres and higher mitochondrial content.  Carnosine was able to partially reverse the level of carbonylation, both basally and post-exercise.

Effects of dipeptides on the contractile activity of muscles were studied in isolated neuromuscular preparations of m. sartorius from the frog Rana temporaria. The neuromuscular preparations were immersed in a bath with Ringer solution, and their rhythmic contractions were recorded in the absence or the presence of test agents. Carnosine was added to the system at the stage of pronounced fatigue, and pH values of control and experimental solution were adjusted to be equal to one another to eliminate the buffer effect. In further experiments, equal amounts of Tris-HCl or other buffering agent were added to the Ringer solution for control and experimental neuromuscular preparation to maintain the pH of the solutions at an equal level. Carnosine and other compounds were added in a concentration equal to their normal concentration in muscles (10-15 mM). Carnosine caused a rapid and effective increase in the contraction force of exhausted preparations. The preparations treated with carnosine demonstrated ability for long- term muscular work, which was even greater than the working capacity of the muscle after long term rest.