Abstract
In the course of a comparative study of the effect of ephedrine and epinephrin on the chromatophores of the Squid, Loligo Pealii, it was observed that these drugs antagonize the stimulating action of barium chloride, the extracts of the parathyroid and anterior as well as the posterior lobe, pituitary gland. Epinephrin is not effective as a rule after barium chloride in mammals. Roth 1 described a good case of such action in the frog. Fawcett, Beebe, et al., 2 found that the stimulation by the extracts of various glands on the uterus of the cat could likewise be inhibited by epinephrin. It is therefore interesting to note that invertebrate smooth muscle cells which appear to be under the control of the sympathetic nervous system exhibit actions similar to the above.
It was found that epinephrin is about twenty times as effective as ephedrine in antagonising the action of the extracts of the parathyroid and the anterior lobe of the pituitary gland; twice as effective in antagonising the action of the extract of the posterior lobe of the pituitary gland. Ephedrine is almost ten times more effective than epinephrin in antagonising barium chloride. (This work will be published in full elsewhere.)
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