Die Wirkung einiger aliphatischer α-ω-Bis-quarternärer Ammonium-Verbindungen auf die Skelettmuskulatur

Activity of analogues of decamethonium on the chick biventer cervicis preparation

The abilities of various decamethylenebisammonium compounds to cause contracture of the chick biventer cervicis preparation have been compared quantitatively with that of decamethonium. In the compounds tested the 1,10 substituents were similar and were ethyldimethylammonium, diethylmethylammonium, triethylammonium, hydroxyethyldimethylammonium and acetoxyethyldimethylammonium; decamethylenebisdimethylamine was also tested. The activity of the bisethyldimethylammonium compound is about one-third of that of decamethonium, that of the bisdiethylmethylammonium compound about one-twenty-eighth, but the other compounds are much less than one-hundredth as active. Even the bistriethylammonium compound, however, has some detectable activity although it is only a partial agonist. It is suggested that ability to depolarize the preparation depends upon the presence of methyl groups attached to the quaternary ammonium atom and also upon the presence of two such onium groups at the ends of the decamethylene chain. In these compounds the acetoxy group reduces ability to depolarize the preparation.

SOME EFFECTS OF LONG CHAIN POLYMETHYLENE BISONIUM SALTS ON JUNCTIONAL TRANSMISSION IN THE PERIPHERAL NERVOUS SYSTEM

A survey has been made of the effects on junctional transmission of the complete series of polymethylene bis-trimethylammonium (BTM) and bis-triethylammonium (BTE) salts from the decamethylene compounds (BTM 10 and BTE 10) to those with twenty-one methylene groups in the chain. These were tested for their ability to cause contracture of the isolated chick biventer cervicis preparation, and for their ability to block the twitch responses of this preparation, those of the rat isolated diaphragm preparation, and those of the cat tibialis anterior preparation. They were also tested for their ability to block transmission in the cat superior cervical ganglion, to block the actions of acetylcholine on the guinea-pig isolated ileum, and for ability to inhibit the hydrolysis of acetylcholine by acetylcholinesterase. Their electrical conductivity has been measured in aqueous solution. Ability to cause contracture of the chick biventer cervicis is confined to the compounds BTM 10 to 15; BTE 10, 11 and 12 have some weak activity but the other BTE compounds, and the BTM compounds with more than fifteen methylene groups, have virtually no activity. In the BTE series both neuromuscular blocking and ganglion-blocking activities increase with chain length up to a maximum in the region of BTE 15 to 17 and then decline. In the BTM series ganglion-blocking activity increases with chain length in much the same way as in the BTE series, though the maximum activity is at a slightly longer chain length. At the neuromuscular junction an increase in chain length beyond BTM 10 leads to a decline in activity but this returns to some extent at longer chain lengths, reaching a second maximum at BTM 18, above which it declines further. At the ganglion BTE 16 is only slightly more active than BTM 16 and about five-times as active as hexamethonium; at the neuromuscular junction in the cat BTE 16 is about five-times as active as BTM 16 and about eight-times as active as (+)-tubocurarine. The affinity of the BTE compounds for the postganglionic acetylcholine receptors of the guinea-pig ileum reaches a maximum at BTE 14 but does not decline significantly with further increase in chain length. Anticholinesterase activity, likewise, does not alter significantly between BTM 12 and BTM 21 and the activity of the compounds in the BTE series appears to be similar. This property could conceivably be modifying the actions of some of the intermediate compounds but is not likely to be affecting those of the more active ones. The conductivity experiments indicate that micelle formation could be limiting the actions of the compounds with 20 or 21 methylene groups, but is not likely to be affecting those of the other compounds. The results suggest that there is a regular increase with chain length of the affinity of these compounds for the receptors in the ganglia and at the neuromuscular junction but that efficacy in causing contracture is limited to compounds with three methyl groups in the cationic head and a chain of about ten methylene groups. The connexion between this ability to depolarize and the ability to block transmission by desensitization is discussed.

The use of short-acting relaxants in E.C.T

Since the introduction of curare to modify the contractions in E.C.T., the use of relaxants has become standard psychiatric practice. These substances reduce the risk of fractures and enable treatment to be given to patients who would otherwise be denied it owing to risks arising from concomitant physical disease. During recent years great efforts have been made to simplify the technique of muscle relaxation, in particular to evolve a method which is short in duration, free from undesirable side-effects and easy in use. In this short paper we give a description of our experience with three drugs recently introduced, namely, Suxamethonium Bromide or Brevidil “M” which we used in 111 treatments, Suxethonium Bromide or Brevidil “E” (70 treatments), and Suxamethonium Chloride or Scoline (653 treatments). These choline succinic ester derivatives have similar characteristics which can be considered together.