Action of decamethonium iodide (C 10) on the demarcation potential of cat's muscle / B. Delisle Burns, W.-D.-M. Paton and M. Vianna Dias.

  • Burns, B. Delisle (Benedict Delisle)
Date:
[1949?]
Catalogue details

Licence: In copyright

Credit: Action of decamethonium iodide (C 10) on the demarcation potential of cat's muscle / B. Delisle Burns, W.-D.-M. Paton and M. Vianna Dias. Source: Wellcome Collection.

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    Oil REFERENCES. Brown G. L. and Goffart M.; J. Physiol.; 1949 ; 108 ; 42 p. Brown G. L. and Burns B. D.; J. Physiol.; 1949 ; 108 ; 54 p. Paton W. D. M. andZAiMis E. J.; J. Physiol.; 1949 ; 108 ; 55 p. DISCUSSION. Beccari. — The very interesting researches of Drs. Burns, Paton and Vianna Dias on the depolarizing action of [Ci0] upon the neuromuscular regions, claim our attention to the chemical behaviour of the quaternary ammonium iodides. Containing nitrogen in the excited state s2 ps, such compounds are highly reactive and may play a part not only in respiratory processes involving pyridinic enzymes, but also in transmethylation equili¬ bria, redox equilibria, and, if nitrogen passes into the non excited state s p.s, they become soluble in lipoids producing a change in the partition coeffi¬ cient at the interfaces. These considerations may furnish a possible expla¬ nation of the puzzling gauntlet of antagonisms observed between [Cio] and [C5], curare and [Cio], curare and acetylcholine, etc., upon different effec¬ tors, though the depolarizing action of such agents with respect to the mem¬ branes might appear to be the same. Therefore it would1 be of interest to see if molecules of very low chemical reactivity, or non reacting at all with the living matter, would be able to act upon the membrane polarization in the synaptic junctions. We have I found two series of metal complexes with a-a'-dipyridil and with ortho- ■ phenanthroline, of the coordinative form [Me(Ci0H8N2)3]++ and j [Me(Ci2H8N2)3] ++, which seem to satisfy these conditions. The iron j compounds have been used for a basal series of experiments. I On the synaptic activity of the spinal cord they demonstrate excitatory effects akin to those produced by drugs which are considered to increase depolarization (strychnine, curarine, eserine) : the dorsal and ventral root potentials are enhanced, summation may occur and long lasting spike discharges up to continuous activity have been observed. On the contrary, I the neuromuscular transmission is completely blocked : all the features f described for the end plate potentials in curarized muscles have been found j with the iron complexes; however the time during which the « supernormal 4 effect» due to a second nerve volley may be obtained, exceeds largely, up 1 0 20-30 folds, the « supernormal period » of curare at 20 C. room tempe¬ rature. Nerve fibres, even after soaking 48 hours in N/100 solutions, are ftill able to conduct impulses; it seems therefore that only the synaptic membranes are particularly accessible to the compounds mentioned. 7-