The Physiological Action of Choline and Neurine. 



91 



" The Physiological Action of Choline and Neurine." By F. W. 

 Mott, MIX, F.E.S., and W. 1). Halliburton, M.D., F.RS. 

 Eeceived March 13 — Bead April 20, 1899. 



(Abstract.) 



The cerebro-spinal fluid removed from cases of brain atrophy, particu- 

 larly from cases of General Paralysis of the Insane, produces when 

 injected into the circulation of anaesthetised animals (dogs, cats, 

 rabbits), a fall of arterial blood pressure, with little or no effect on 

 respiration. This pathological fluid is richer in proteid matter than 

 the normal fluid, and among the proteids, nucleo-proteid is present. 

 The fall of blood pressure, is, however, due not to proteid, nor to inor- 

 ganic constituents, but to an organic substance, which is soluble in 

 alcohol. This substance is precipitable by phospho-tungstic acid, and 

 by chemical methods was identified as choline. The crystals of the 

 platinum double salt, which, when crystallised from 15 percent, alcohol, 

 are characteristic octahedra, form the most convenient test for the 

 separation and identification of this base. 



The nucleo-proteid and choline doubtless originate from the disinte- 

 gration of the brain tissue, and their presence indicates that possibly 

 some of the symptoms of General Paralysis may be due to auto-intoxi- 

 cation ; these substances pass into the blood, for the cerebro-spinal fluid 

 functions as the lymph of the central nervous system. We have iden- 

 tified choline in the blood removed by venesection from these patients 

 during the convulsive seizures which form a prominent symptom in the 

 disease. 



Normal cerebro-spinal fluid does not contain nucleo-proteid or choline, 

 or if these substances are present, their amount is so small that they 

 cannot be identified. Normal cerebro-spinal fluid produces no effect on 

 arterial pressure ; neither does the alcoholic extract of normal blood or 

 of ordinary dropsical effusions. 



The presence of choline in the pathological fluids will not explain 

 the symptoms of General Paralysis ; for instance, it will not account 

 for the fits just referred to. Its presence, however, is an indication 

 that an acute disintegration of the cerebral tissues has occurred. If 

 other poisonous substances are also present, they have still to be dis- 

 covered. 



Our proof that the toxic material we have specially worked with is 

 choline, rests not only on chemical tests, but also on the evidence 

 afforded by physiological experiments ; the action of the cerebro-spinal 

 substance exactly resembles that of choline. Neurine, an alkaloid 

 closely related to choline, is not present in the fluid ; its toxic action is 

 much more powerful, and its effects differ considerably from those of 

 choline. 



