A text-book of pharmacology and therapeutics; or, The action of drugs in health and disease, . principleinduces the spasmodic form, but it is not unlikely that this also arisesfrom ergotoxine acting in poorly nourished individuals. Action.—The action .of ergot. in the living organism has onlyrecently been elucidated by the admirable ex|ierimental work of Dale,and is due to the ergotoxine, tyramine and ergamine. The first two ERGOT -wo of these resemble adrenaline in some of their effects, and like it act onthe myoneural junctions of the true sympathetic ner\es. But wiiileadrenaline stimulates
A text-book of pharmacology and therapeutics; or, The action of drugs in health and disease, . principleinduces the spasmodic form, but it is not unlikely that this also arisesfrom ergotoxine acting in poorly nourished individuals. Action.—The action .of ergot. in the living organism has onlyrecently been elucidated by the admirable ex|ierimental work of Dale,and is due to the ergotoxine, tyramine and ergamine. The first two ERGOT -wo of these resemble adrenaline in some of their effects, and like it act onthe myoneural junctions of the true sympathetic ner\es. But wiiileadrenaline stimulates these junctions indiscriminately whether they aremotor or inhibitory in character, tyramine appears to aftect the motorones more than the inhibitory, while ergotoxine does not act on theinhibitory junctions at all. And ergotoxine, while stimulating themotor myoneural junctions in small doses, paralyzes them in largeramounts. These bases are much less powerful than adrenaline, buttheir effects last longer and can be elicited by hypodermic injection Fig. 36 Leg volume —120 mm.—lie __l|_J_J l_! \ I I I I L .4. B Figures illustrating the effects of ergotoxine on the blood-pressure (Dale). In A theinjection induces a rise of blood-pressure () with constriction of the vessels of theleg. In 5 a large dose of ergotoxine had been injected previously, and adrenaline injectedat the point indicated now causes a fall of blood-pressure with dilatation of the intes-tinal vessels. or even by administration by the mouth. Tyramine is prol)ably ofless importance in the action of ergot than ergotoxine, which alongwith ergamine is responsible for the chief effects of the drug. Ergaminediffers from the other bases in acting not on the nerve junctions, buton the unstriated muscle cells directly, and its action varies consider-ably in different species of animals and even in different organs of thesame animal. Circulation.—Ergotoxine or tyramine injected intravenously causesan abrupt
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttherapeutics, bookyea
