Neuromuscular blocking properties of some bistropinium esters

The neuromuscular blocking, anti-acetylcholine and ganglion blocking properties of two series of bistropinium esters were examined. The neuromuscular blocking activities of the mandelic acid esters of NN'-polymethylenebis(tropinium halides) were found to depend upon the number of carbon atoms (n) in the linking chain. Potency was enhanced more than 50 times as n was increased from 2 to 7. Compounds in which n equalled 7, 8, 9, 10 and 12 differed little in activity, but were generally more potent than tubocurarine in cats and rabbits. A peak of ganglion blocking action was obtained at the pentamethylene member. Esterification enhanced the feeble neuromuscular blocking properties of NN'-decamethylenebis(tropinium halide), the mandelic acid ester being more effective than the tropic, benzoic or phenylacetic acid esters in cats and rabbits. When two benzoic or mandelic acid esters of tropine were linked through their nitrogen atoms by a phenylenedimethyl grouping (-CH(2).C(6)H(4).CH(2)-), meta substitution was more effective than was ortho or para in producing neuromuscular block. The effectiveness of esterifying acids in m-phenylenedimethyl derivatives decreased in the following order, phenylacetic> tropic or mandelic>benzoic>acetic and diphenylacetic.

Renal tubular effects of ammonium salts on electrolyte transport

It has been established that ammonia salts exert a direct renal tubular effect in the chicken. The injection of ammonium chloride into the renal portal circulation produces a predominantly unilateral effect, characterized by inhibition of both the reabsorption of sodium, chloride, bicarbonate, and water and the secretion of potassium and hydrogen ions. An increase in total ammonia excretion was also observed. The inhibition of electrolyte and water transport is independent of the anion infused. Natriuresis and diuresis are produced by the ammonium salts of chloride, sulfate, nitrate, and acetate. The effect is not dependent upon the development of metabolic acidosis. Furthermore, an increase in endogenous ammonia production and excretion provided by the infusion of precursor amino acids does not interfere with electrolyte transport. Thus, the inhibitory effect of ammonium salts is probably a consequence of an increase in the concentration of ammonium ion in the peritubular circulation. The results are consistent with the thesis that ammonium ion may substitute for potassium on the linked sodium-potassium exchange pump on the contraluminal surface of the renal tubule cell.