Abstract
In 1911 Straub and later his pupil Herrmann described a biological reaction for morphine which they thought was specific for that alkaloid and could possibly be used in forensic work. 1 , 2 They noted that after injections of small amounts of morphine in mice there followed a peculiar stiffening and bending backwards or curling of the tails of those animals. No adequate explanation of this phenomena was given by the authors. In May, 1918, Van Leersum 1 described the same phenomenon in the rat and showed that this peculiar stiffening and upbending of the tail was really due to a spasm of the sphincters of the anus and especially of the bladder and that the same phenomenon could be produced by exciting spasm of the sphincters by other agents, chemical or physical. The researches of the present author on the influence of various opium alkaloids on smooth muscle, which were first reported before the Pharmacological Society in December, 1917, 2 and later, in the PROCEEDINGS OF THE SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE in February, 1918, throw additional light on the mechanism of Straub's phenomenon. The author has shown that in respect to their action on plain muscle, the opium alkaloids fall in two groups: the piperidine-phenanthrene group of which morphine is the principal member, and the benzylisquinoline group, of which papaverin is the principal member. It was shown that morphine stimulates the contractions and increases the tonus of smooth muscle, while papaverin inhibits the contractions and lowers the tbn'us of the same.3 Injections of morphine in the mouse and rat produce a spasmodic contraction of the bladder and its sphincters, and this probably plays the important r81e in the production of Straub's phenomenon.
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