V. the Influence of Caffeine on Lactic Acid Formation

THE production of rigor in skeletal muscle by the action of caffeine, discovered by Cogswell [1852], has formed the subject of several investigations. Ransom [1911] showed that the rigor is accompanied by lactic acid production, and this was confirmed and the conditions of lactic acid forbnation further studied by Meyerhof [1921] and by Matsuoka [1924]. The alterations in the lactacidogen content of the muscle submitted to the action of caffeine was studied by Riesser and Neuschloss [1922], whilst the effects on heat production were studied by Hartree and Hill [1923]. From these researches it would seem that the effect of caffeine is greatly to accelerate the breakdown of glycogen and of lactacidogen into lactic acid, by unloosing a chain of processes similar to those which ensue upon stimulation of the muscle; in presence of oxygen, the oxygen usage of the muscle is greatly increased though there does not appear to be any restitution of lactacidogen. The rigor which is produced in striated muscle by high concentrations of caffeine is irreversible, and is accompanied by destruction of the structure of the muscle fibres, which has been studied by Secher [1914]. In a recent publication [Evans, 1925], I hinted that caffeine did not appear to cause acceleration of lactic acid production in plain muscle, and it is the further investigation of this point which forms the subject of the present communication.