Changes occurring in mammalian muscle immediately after death.

Abstract

In the numerous observations made in recent years on the chemical changes which set in after death in muscle, little attention has been paid to those which occur in mammalian muscle during the first few minutes after the cessation of blood flow. The increase which occurs in free phosphorus after two hours incubation of muscle juice or chopped muscle, and from which the so-called lactacidogen is calculated, has not been clearly linked up with the changes which take place in glycogen, lactic acid and free sugar. In the theories of Meyerhof, A. V. Hill, and their co-workers, with regard to muscular contraction, it is considered that lactic acid is very rapidly formed from glycogen. But this cannot occur directly; there must be some intermediate carbohydrate, and it was to obtain evidence of this that present investigation was undertaken. That such a substance may be formed in muscle during the action of insulin is suggested by various observers. The muscles were rapidly dissected from one hind limb of a rabbit immediately after stunning, and frozen to a brittle mass with liquid air. After thorough pulverization in an iron mortar, quantities of from 3 to 5 gm. each of the powdered muscle were placed in weighed vacuum tubes. After all the tubes had again been weighed, equal volumes of 0.9 per cent NaCl solution were added to each, and they were evacuated and well shaken at room temperature. At intervals of 3 to 5 minutes tubes were then taken for the determination of glycogen, free sugar, total carbohydrate, free phosphorus and lactic acid. The results of a typical experiment are shown in curve form. The free sugar in this particular experiment was that found in the Schenck filtrate, but the results are the same in numerous others in which the sugar was dissolved out from the muscle by 80 per cent alcohol.