ANEURINE (THIAMINE) 



kg. E. L. Stem ^ found that 600 mg. administered by cisternal 

 puncture killed a cat. 



According to T. J. Haley, ^** aneurine nitrate had approximately 

 the same acute toxicity for mice and rabbits as had the hydrochloride. 



Effect on Isolated Tissues and Organs 



The effect of solutions of aneurine on isolated tissues and organs 

 has been studied by many workers. A dilution of i in 1000 to 10,000 

 produced acceleration and an increase in the amplitude of the isolated 

 frog's heart. ® A dilution of i in 1000 increased the tonus of the exposed 

 frog's heart, but at higher concentrations,' aneurine acted as a cardiac 

 depressant due to acidity and hypertonicity. A dilution of i in 1000 

 depressed the frog's ventricle to stoppage at p}l 5-2 to 6-o, and a 

 similar, though less marked, effect was produced by a dilution of i in 

 10,000 ; I in 100,000 had no effect. Cocarboxylase also had a de- 

 pressant effect at pB. values up to 7-6. The depressant effect was not 

 annulled by atropine.^ Dilutions of i in 1000 to 10,000 produced 

 coronary dilatation and an increase in the amplitude of the perfused 

 rabbit's heart. ^ 



The movements of the perfused isolated rabbit's intestine were 

 increased and the rhythm of the isolated rabbit's uterus was inhibited 

 by dilutions of i in 100 to 10,000, but augmented by a dilution of i in 

 100,000. The contractions of skeletal muscle were decreased by 

 aneurine in a dilution of i in 1000.^ Aneurine and cocarboxylase 

 inhibited the action of nicotine on the isolated rabbit and guinea-pig 

 intestine and on the isolated striated muscle of the frog ; these effects 

 were not influenced by prostigmine.^ The total work output of 

 frog's gastrocnemius muscle, when perfused with Ringer's solution 

 and stimulated electrically, was significantly increased by the addition 

 of aneurine ^° up to concentrations of o-ooi millimoles per litre. 

 Aneurine pyrophosphate had a greater effect at lower concentrations, 

 and an equal effect at o-ooi millimoles per litre. When the sciatic 

 nerve of a frog was stimulated and frozen in liquid air, the stimulated 

 nerve liberated aneurine, as shown by rat bradycardia.^^ The total 

 aneurine in frog's nerve after poisoning with iodoacetate remained 

 the same after stimulation, but the free aneurine fell to half the 

 amount present in the non-stimulated nerve. ^^ This difference is 

 believed to be due to the effect of iodoacetate on phosphorylation. 



The aneurine content of guinea-pig's sciatic nerve diminished after 

 cutting the nerve and in fifty to seventy hours fell to 40 to 50 % of 

 the amount present in a control nerve. ^^ Stimulation of the branch 

 of the vago-sympathetic nerve fibres supplying the heart of the frog 

 led to the liberation of aneurine, or a compound resembling it, as well 



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