A comparison of the effects of 4-dimethylaminopyridine and 4-aminopyridine on isolated cardiac and skeletal muscle preparations.

Paper

A comparison of the effects of 4-dimethylaminopyridine and 4-aminopyridine on isolated cardiac and skeletal muscle preparations.

Published Feb 1, 1985 · S. Ao

Archives internationales de pharmacodynamie et de thérapie

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2

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0

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Semantic Scholar

Abstract

: The actions of 4-dimethylaminopyridine (4-dimethyl-AP) on the isolated rat diaphragm and guinea-pig atria were examined and compared with those of 4-aminopyridine (4-AP). In the rat diaphragm, 4-dimethyl-AP slightly (27%) increased indirectly evoked maximal twitches, and was a weak antagonist of d-tubocurarine-induced neuromuscular block, while 4-AP increased indirect twitches by about 250%, and produced rapid and complete reversal of d-tubocurarine block. In directly stimulated preparations, 4-AP but not 4-dimethyl-AP produced marked augmentation of maximal twitches (220%). In electrically-driven guinea-pig left atria, both compounds produced positive inotropic effects (PIE), which were partially inhibited by L-propranolol or by pretreatment with intraperitoneal syrosyngopine or 6-hydroxydopamine, suggesting that part of the response was due to noradrenaline (NA) release. Nifedipine or methoxyverapamil (D-600) produced negative inotropic effects (NIE) and prevented the PIE of both aminopyridines. The NIE of these Ca2+ entry blockers was reversed by excess CaCl2 or NA. It is concluded that 4-dimethyl-AP, like 4-AP is a powerful cardiac inotropic agent in vitro. 4-Dimethyl-AP which, unlike 4-AP, possesses weak effects on neuromuscular transmission and on muscle contractility in the rat diaphragm, therefore appears to possess a greater specificity for cardiac muscle.

In Vitro Study

Study Snapshot

4-dimethyl-AP is a powerful cardiac inotropic agent, but has weaker effects on neuromuscular transmission and muscle contractility, suggesting a greater specificity for cardiac muscle.

PopulationOlder adults (50-71 years)

Sample size24

MethodsObservational

OutcomesBody Mass Index projections

ResultsSocial networks mitigate obesity in older groups.

Paper

A comparison of the effects of 4-dimethylaminopyridine and 4-aminopyridine on isolated cardiac and skeletal muscle preparations.

References

Citations

The myoneural effects of lithium chloride on the nerve-muscle preparations of rats. Role of adenosine triphosphate-sensitive potassium channels.

Lithium chloride inhibits diaphragmatic contractions in rats, enhancing paralysis induced by pipecuronium or succinylcholine, and can be combined with other drugs to enhance its effects.

Effects of 4-aminopyridine on demyelinated axons, synapses and muscle tension.

4-aminopyridine improves symptoms in multiple sclerosis patients through potentiation of synaptic transmission and increased muscle twitch tension, independent of demyelination.