196 NUCLEIC ACIDS AND THE NITROGENOUS BASES 



THE NITROGENOUS BASES DERIVED FROM THE PHOSPHOLIPINS. 



The saponification of the Lecithins by alkalies yields, besides soaps 

 and the glycerophosphate of the alkali, a nitrogenous base, Choline 

 or trimethyloxyethylammonium hydroxide. 



/CH 2 .CH 2 OH 



(CH 3 ) 3 i N< 



X OH 



It is a strong base, yielding alkaline solutions and forming a double 

 salt with platinic chloride. By the saponification of Kephalins, how- 

 ever, we obtain a different base, namely Amino-ethyl Alcohol. 



H 2 N.CH 2 .CH 2 OH 



from which choline is probably derived by methylation. 



There has been much discussion of the question whether or not 

 a third and related base, Neurine, or vinyltrimethyl ammonium 



hydroxide : 



/CH:CH 2 



* (CH 3 ) 3 i N< 



X OH 



is yielded by the hydrolysis of Protagon, but the consensus of opinion 

 appears now to coincide with the view originally expressed by Gule- 

 witsch, that neurine is in reality a putrefaction-product derived from 

 choline by the action of bacteria. Thus perfectly fresh brain-tissue 

 does not appear to yield neurine at all, unless the lecithins (or protagon) 

 are boiled with strong alkalies which, even in pure solutions, results in 

 a partial conversion of choline into neurine. 



Both choline and neurine exert the physiological actions which are 

 typical of all the trimethylamine derivatives. The first symptom of 

 poisoning is salivation, followed by intestinal cramps. There is a 

 preliminary fall in blood- pressure succeeded by a rise. Death is 

 ultimately due to arrest of the heart. These symptoms arise from 

 stimulation of sympathetic nerve-endings in the glands or muscles 

 affected and are prevented by the administration of Atropine which 

 paralyzes these junctions. 



It was at one time thought that free choline might occur in the brain, 

 particularly in degenerative changes of the central nervous system, 

 and that under these conditions choline might be found in the cerebro- 

 spinal fluid. The presence of choline in cerebrospinal fluid was, in 

 fact, suggested as a means of detecting degenerative lesions of the 

 brain. Since platinic chloride must be employed to detect the small 

 quantities of choline looked for, however, and potassium and ammonium 

 salts, both of which are also present, yield very similar crystalline 

 platinichlorides, it is rather probable that the crystals obtained from 

 cerebrospinal fluid are not in reality compounds of choline. The 



