Tissue Lactates and Blood Lactates as Affected by Muscular Exercise.

In dogs anesthetized with amytal the following preparations were made: 3 fore limb muscles and 2 hind limb muscles were prepared for rapid excision, with care to avoid injury to said muscles or interference with their blood and nerve supply. A carotid artery was cannulized, and a brachial vein and the inferior vena cava below junction with the renal veins were exposed. The blood vessels leading to both kidneys were tied off. Stimulating electrodes were imbedded under the skin of the back at the levels of the first lumbar and last sacral vertebrae. 1

Continuous records of arterial blood pressure and of oxygen consumption were made. At the end of a 15-minute basal period a sample of arterial blood was drawn and one fore limb muscle rapidly excised and thrown at once into liquid air. Artificial exercise (confined to the hind quarters by the location of the electrodes) was then induced for 15 minutes. At the end of the exercise period blood samples were drawn from the cannulized artery, from the inferior vena cava (representing the outflow from worked muscles) and from the brachial vein (representing the outflow from non-worked muscles). One hind limb muscle (worked) and one fore limb muscle (non-worked) were excised rapidly and thrown into liquid air.

At the end of a recovery period approximately one hour in length blood samples were again drawn, as above, and one previously worked and one non-worked muscle excised and thrown into liquid air. Blood and muscle lactates were determined by the method of Friedmann, Cotonio and Shaffer. 2

The results of 5 experiments are summarized in Table I.