Depressor Action of Extracts of Burned Skin

Abstract

Extracts were made of normal and burned skin of rabbits by the method of Chang and Gaddum. The skin was burned at temperatures varying from 70°C. to 210°C. and removed from 3 minutes to 48 hours after burning. The extracts were then tested by their action after intravenous injection on the blood pressure of 7 rabbits and 10 cats. Results. Extracts of burned skin of 10 anesthetized rabbits caused an immediate, but transient, fall in blood pressure. The curve was similar to that following acetylcholine, but the recovery was slower and was not always followed by a rise above the original level. Recovery was slower in the rabbit than in the cat. The depressor action was not affected by the injection of atropine (0.1 mg. per kg.), and was not reduced by treating the extract with alcohol to precipitate adenosine and its derivatives; and since depression of the blood pressure of rabbits was obtained, the depressor substance was not mainly histamine. Later experiments showed that when the extract was boiled with alkali and then neutralized, the depressor action did not disappear. The substance mainly responsible for the action was therefore not the “P” substance of Euler and Gaddum. The depressor substance has not been identified. Extracts of normal skin of 5 rabbits were qualitatively similar to those of burned skin in depressor action. Quantitative Comparisons. The depressor action of the extracts was compared with that produced by a standard solution of acetylcholine and roughly expressed in γ of acetylcholine equivalent per gm. of tissue. The extracts are named according to the time after burning or removal of tissue and to the temperature at which the heat had been applied.