Locke's vs. Tyrode's For Perfusion of Segments of Intestine.

Abstract

In previous work Tyrode's solution seemed to be inferior to Locke's for the perfusion of intestinal segments. MacLeod 1 states: “Although undoubtedly superior for some perfused preparations, such as the intestine, it does not seem to be in any way superior to Locke's for the perfusion of the heart.” It seemed desirable to investigate further the value of these solutions for intestinal perfusion under the ordinary laboratory procedure.

Segments of the small intestine of the rabbit and cat were used. The segments were taken well below the duodenum because the jejunum and ileum are less erratic in activity.

The solutions used were: Locke's 2 NaCl, 0.90%; KCl, 0.042%; NaHCO₃, 0.032%; CaCl₂-2H₂O, 0.024%; dextrose, 0.1%. Tyrode's 3 NaCl, 0.80%; KCl, 0.02%; NaHCO₃, 0.10%; CaCl₂-2H₂O, 0.02%; MgCl₂, 0.01%; NaH₂PO₄, 0.005%; dextrose, 0.1%. The salts were accurately weighed and the solutions freshly prepared. The same stock of C. P. chemicals was used throughout. The Magnus type of apparatus was used, the volume of which was 200 cc.

The animal was stunned, bled from the carotid artery, and the abdomen opened at once. A segment was taken well below the duodenum and from this the required number of smaller segments were cut and dropped into their respective solutions. As short a period of time as possible was allowed to elapse from the moment the animal was stunned until the individual segment was attached to its respective piece of apparatus.

The pH of the solutions was obtained by the quinhy drone electrode. When a change of pH was desired a bath of warmed fresh solution was substituted for the bath already in use. When adrenalin was used, 1 or 2 drops of 1 to 10,000 solution prepared from Adrenalin, 1 to 1,000, Parke Davis, was added to the bath at a constant point.