The physiological action of indolethylamine / by P.P. Laidlaw.

  • Laidlaw, Patrick Playfair, 1881-1940.
Date:
1911
Catalogue details

Licence: In copyright

Credit: The physiological action of indolethylamine / by P.P. Laidlaw. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    doses of the new base must be central in origin, for no evidence of salivary secretion could be obtained in the anaesthetised animal. The pancreatic secretion in the dog is unalfected bj^ indolethylamine. Ten milligrams of indoleth^Tamine were given intravenously to an anaesthetised cat in which the urinary secretion was being recorded. A marked slowing of the urine flow was observed during the rise of blood pressure, which, however, soon jjassed oif. The effect is in all probability the expression of a transient constriction of the arterioles of the kidney. Experiments in conjunction with Mr. A. J. Ewins, are in progress with regard to the metabolism of the new base. Note ox the Eormatiox of Ikdolethylamixe from Tryptophane It has been shown by several observers that putrefactive micro- organisms will remove CO2 from amino-acids and form the corresponding amine. It was thought possible that indolethylamine might be made in this manner from tryptophane. number of experiments were carried out with different mixtures of bacteria: onl}^ one of them proved successful. 0’5 gram tryptophane was dissolved in 250 c.c. of a simple culture medium.^ This was then infected from a putrid pancreas subculture which had been shown to be capable of forming /j-iminazolyl- ethylamine from histidine and p.hydrox^^phenylethjTamine from tyrosine. After one fortnight’s incubation the mixture was found to produce a good rise of blood pressure, and indolethylamine could be isolated from it. The mixture was boiled with charcoal and filtered. It was then evaporated to about lUO c.c. and excess of picric acid added. On cooling, the highly insoluble indolethylamine picrate sej^arated out as a deep orange-red crystalline precipitate. The crude product was then recrystallised from alcohol and again from aqueous acetone, when crystalline form, colour reactions, melting point, and physiological action were found to be identical with those of the synthetic product. The yield from the one experiment which went in the desired direction was poor, about 140 mgm. of pure picrate being obtained from 0’5 gram tryptophane. Summary (I) Indolethylamine produces a transient stimulant effect upon the central nervous system, causing clonic and tonic convulsions, tremors of limbs, and vaso-constriction. (II) It has a direct stimulant action on plain muscle, wliich is mosf marked in the arterioles, tlie iris, and the uterus. (III) The formation of indolethylamine from Irvpfophane by bacterial action is described. 1. Peptone 2 gnu., dextrose 8 grin., trace sodium phosphate, trace magnesium sulphate, precipitated calcium carbonate 5 grin., and tap water to the litre.