Straub's Morphine Reaction. 



ioi 



or curling of the tails of those animals. No adequate explanation 

 of this phenomena was given by the authors. In May, 191 8, 

 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, 191 7, 2 

 and later, in the Proceedings of the Society for Experimental 

 Biology and Medicine in February, 191 8, 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 benzyl- 

 isoquinoline group, of which papaverin is the principal member. 

 It was shown that morphine stimulates the contractions and in- 

 creases the tonus of smooth muscle, while papaverin inhibits the 

 contractions and lowers the tonus 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 rdle in the production of Straub's phenomenon. Van 

 Leersum described the vesical spasm after morphine injections as 

 being of spinal origin. Inasmuch as Macht's experiments were 

 performed on isolated tissues, including the sphincters of the 

 rectum and the bladder, we are forced to regard Straub's phe- 

 nomenon as being at least in part due to a peripheral effect of 

 morphine. 



Further work by the present author sheds more light on the 

 subject. Inasmuch as the morphine molecule structurally is a 

 combination of piperidine and phenanthrene nuclei, experiments 

 were made to determine the effect of phenanthrene and piperidine 

 separately on plain muscle. Experiments with phenanthrene 

 itself revealed that it has no effect on plain muscle. Phenan- 



1 Van Leersum, Nederland. Tijschft. voor Genesk, 1912, LXII, 1374. 



2 Macht, Jour. Pharmacol, and Exp. Therap., 1918, XI, 176. 

 8 Macht, Jour. Pharmacol, and Exp. Therap., 1918, XI, 389. 



