Effects of 3,4-diaminopyridine on mechanical and electrical responses of frog single muscle fibres.

@article{Khan1983EffectsO3,
  title={Effects of 3,4-diaminopyridine on mechanical and electrical responses of frog single muscle fibres.},
  author={R. Khan and M. Lemeignan},
  journal={Acta pharmacologica et toxicologica},
  year={1983},
  volume={52 3},
  pages={
          181-7
        }
}
The effects of 3,4-diaminopyridine (3,4-DAP) were studied on isolated muscle fibres of the frog in concentrations ranging between 0.025 and 5.0 mM. Isometric twitch and tetanus responses were recorded at temperatures between 2.5 and 3.9 degrees. 3,4-DAP caused a concentration-dependent increase in twitch amplitude, maximum effects being obtained at a concentration of 3 mM with a mean increase in tension of 70 +/- 12% of control (n = 7). 3,4-DAP in 3 mM concentration had only a slight increase… Expand
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References

SHOWING 1-10 OF 21 REFERENCES
The effects of 3,4-diaminopyridine on acetylcholine release at the frog neuromuscular junction.
TLDR
It is concluded that 3,4-DAP is a useful tool in the study of both evoked and spontaneous acetylcholine release, and may be due to the release of performed multiquantal packets of acetyl choline as suggested for vinblastine. Expand
Effects of 4-aminopyridine on the excitation-contraction coupling in frog and rat skeletal muscle.
TLDR
It is concluded that 4-AP potentiates the twitch response by increasing the release of activator calcium into the myofibrillar space by prolongation of the action potential. Expand
Effects of 4-Aminopyridine on Contractile Properties of Skeletal Muscle
ABSTRACT The contractile effects of 4-aminopyridine (4-AP) were studied on isolated muscle fibres of the tibialis anterior and semitendinosus muscles of Rana temporaria (1-4°C) and, in one series ofExpand
Potency of 3,4-diaminopyridine and 4-aminopyridine on mammalian neuromuscular transmission and the effect of pH changes.
TLDR
3,4-Diaminopyridine, like 4-AP, converted the end-plate potential produced by electronic depolarization of tetrodotoxin-blocked frog nerve terminals into an all-or-none response, implying that the drugs enhance transmitter release by greatly increasing the voltage-dependent calcium conductance of the nerve terminal membrane. Expand
Effects of 4-aminopyridine at the frog neuromuscular junction.
TLDR
It is suggested that 4-AP, by prolonging the presynaptic action potential, could increase calcium concentration in the nerve terminal and, thus, the transmitter release in frog neuromuscular junction blocked by d-tubocurarine or low Ca++ high Mg++ medium. Expand
Effects of diethyl-stilboestrol on single fibres of frog skeletal muscle.
  • A. Khan
  • Chemistry, Medicine
  • Acta physiologica Scandinavica
  • 1979
TLDR
It is concluded that diethyl-stilboestrol potentiates the twitch response and prolongs the relaxation time by inhibition of the calcium re-uptake by the sarcoplasmic reticulum. Expand
Effects of 4-aminopyridine on neuromuscular transmission
  • H. Lundh
  • Chemistry, Medicine
  • Brain Research
  • 1978
TLDR
Experiments on the mode of action of 4-AP suggest that the drug increases transmitter release by enhancing the influx of calcium ions during depolarization of the nerve terminal by enhancing its effect on amplitude or time course of mepps. Expand
Dynamics of aminopyridine block of potassium channels in squid axon membrane
TLDR
The data are consistent with a simple binding scheme incorporating no changes in gating kinetics which conceives of aminopyridine molecules binding to closed K channels and being released from open channels in a voltage-dependent manner. Expand
Aminopyridines and sparteine as inhibitors of membrane potassium conductance: effects on Myxicola giant axons and the lobster neuromuscular junction.
TLDR
The effects of the compounds 2-, 3- and 4-aminopyridine and sparteine on membrane conductance changes were examined using both voltage-clamped Myxicola axons and the lobster neuromuscular junction and Sparteine was found to be a more potent, but somewhat less specific, inhibitor of the potassium conductance. Expand
Interactions of aminopyridines with potassium channels of squid axon membranes.
TLDR
It is concluded that aminopyrimidines may be used as tools to block the potassium conductance in excitable membranes, but only within certain specific voltage and frequency limits. Expand
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