RESTING METABOLISM OF THE FROG'S VENTRICLE

¹ The Department of Pharmacology, University of Edinburgh

1. The rate of asphyxial exhaustion of frog's ventricles either normal or poisoned with I.A.A. provides a method by which the rates of metabolism during asphyxia under different experimental conditions can be compared.

2. This method shows a linear relation between the metabolic rate and frequency up to a frequency of 30 per min., a result which agrees with previous estimations of the influence of frequency on the oxygen consumption of the isolated ventricle.

3. The resting metabolism per min. of the normal ventricle is equal to the metabolism per min. added by contraction at a frequency of 3-7 per min., and is 21 per cent. of the metabolism at a frequency of 15 per min.

4. The resting metabolism per min. of the I.A.A. poisoned ventricle is equal to the metabolism added by a contraction at a frequency of 4-8 per min., and is 24 per cent. of the metabolism at a frequency of 15 per min.

5. These results with ventricles poisoned with I.A.A. indicate that phosphagen is utilised by the resting as well as by the contracting ventricle.

6. The duration of survival of the I.A.A. poisoned ventricle when asphyxiated is about that which would be expected if phosphagen hydrolysis were the chief source of energy available.

The expenses of this research were defrayed by a grant from the Moray Research Fund, for which the author desires to express his thanks.