Isolation of a Crystalline Depressor Substance from the Brain

Abstract

It has been shown 1 , 2 , 3 that a depressor substance is present in certain extracts from brain tissue. Major and Weber 2 presented evidence that the active depressor substance was not histamine choline or acetyl choline. Major, Nanninga and Weber 3 presented further evidence that the depressor activity of these brain extracts was not due to either histamine, choline, acetyl choline, adenosine or adenylic acid. We have recently obtained from these brain extracts a crystalline compound which possesses a marked depressor action upon the blood pressure of dogs under ether anesthesia. We have employed the following procedure to obtain the active depressor substance in crystalline form.

After removal of the acetone from the crude acetone extract of brain, 60 gm. of potassium carbonate was added to each 100 cc. of the crude extract. This was extracted with an equal volume of 95% alcohol and the extraction repeated 4 times. This, after standing overnight in the ice-box, was filtered; the filtrate evaporated under partial vacuum to a consistency of a thick syrup and then redissolved in 95% alcohol. Concentrated sulphuric acid mixed with 50 parts of 95% alcohol was added to this solution, producing a heavy flocculent precipitate. The sulphuric acid alcohol mixture was added until no further precipitation was obtained, the solution filtered, neutralized with NaOH and again filtered. The filtrate was then evaporated under a partial vacuum to a thick syrupy consistence, dissolved in water and treated with phosphotungstic acid, which produced a copious white precipitate. This precipitate was separated by filtration, the filtrate evaporated under low pressure to the consistency of a thick syrup and then dissolved in absolute alcohol.