The influence of temperature and frequency of stimulation on the impairment of excitability of frog skeletal muscle by local anesthetics and alkyl amphipathic agents

1985 ◽  
Vol 63 (10) ◽  
pp. 1327-1334 ◽  
Author(s):  
James G. Foulks ◽  
Lillian Morishita
Keyword(s):  
Skeletal Muscle ◽  
Sodium Channels ◽  
Local Anesthetics ◽  
Frog Skeletal Muscle ◽  
Abrupt Increase ◽  
Frequency Dependent ◽  
Temperature Changes ◽  
Influence Of Temperature ◽  
Lipid Environment ◽  
Frequency Of Stimulation

The potency of various types of alkyl amphipathic (cationic, anionic, and neutral) as well as tertiary amine local anesthetics in impairing the excitability of frog skeletal muscle was markedly enhanced by an increase in temperature from 20 to 30 °C. Enhancement of the local anesthetic effects of all types of agents was also produced by a decrease in temperature to 5 °C, but this effect was found to be frequency dependent. With abrupt increase or decrease in temperature, changes in excitability were rapid and unlikely to be the result of changes in the partition of the apolar portions of these molecules into the hydrophobic regions of the sarcolemma. These results are interpreted as indicating that both the presence of local anesthetics and alterations in temperature can influence the rates of potential-dependent changes in the conformation of membrane proteins that control the permeability of excitable sodium channels, possibly by modifying the fluidity of specific portions of their hydrophobic components or their immediate lipid environment. The accumulation of inactivation as the result of incomplete recovery from the effects of preceding depolarizations appears sufficient to explain the frequency-dependent effects produced by these agents.

scholarly journals Modified kinetics and selectivity of sodium channels in frog skeletal muscle fibers treated with aconitine.

1982 ◽  
Vol 80 (5) ◽  
pp. 713-731 ◽  
Author(s):  
D T Campbell
Keyword(s):  
Skeletal Muscle ◽  
Sodium Channel ◽  
Sodium Channels ◽  
State Level ◽  
Steady State Level ◽  
Channel Block ◽  
Frog Skeletal Muscle ◽  
Channel Kinetics ◽  
Ionic Selectivity ◽  
Channel Selectivity

The effect of the plant alkaloid aconitine on sodium channel kinetics, ionic selectivity, and blockage by protons and tetrodotoxin (TTX) has been studied in frog skeletal muscle. Treatment with 0.25 or 0.3 mM aconitine alters sodium channels so that the threshold of activation is shifted 40-50 mV in the hyperpolarized direction. In contrast to previous results in frog nerve, inactivation is complete for depolarizations beyond about -60 mV. After aconitine treatment, the steady state level of inactivation is shifted approximately 20 mV in the hyperpolarizing direction. Concomitant with changes in channel kinetics, the relative permeability of the sodium channel to NH4,K, and Cs is increased. This altered selectivity is not accompanied by altered block by protons or TTX. The results suggest that sites other than those involved in channel block by protons and TTX are important in determining sodium channel selectivity.

Retarded recovery of excitability and twitches of frog toe muscles after K-induced depolarization (slow inactivation) in the presence of alkyl amphipaths

1985 ◽  
Vol 63 (10) ◽  
pp. 1335-1338
Author(s):  
James G. Foulks ◽  
Lillian Morishita
Keyword(s):  
Low Temperature ◽  
Sodium Channels ◽  
Local Anesthetics ◽  
Slow Inactivation ◽  
Frequency Dependent ◽  
High K

Alkyl amphipaths resemble conventional local anesthetics in their ability to retard the recovery of excitability and twitch tension after depolarization at high Ko, an effect that is attributed to slow inactivation of potential-dependent sodium channels. The similar effect of low temperature offers an explanation for its ability to enhance the frequency-dependent effects of these agents.

Inhibition of frog skeletal muscle sodium channels by newly synthesized chiral derivatives of mexiletine and tocainide

1997 ◽  
Vol 356 (6) ◽  
pp. 777-787 ◽  
Author(s):  
Annamaria De Luca ◽  
Fedele Natuzzi ◽  
Giulia Falcone ◽  
Andrea Duranti ◽  
Giovanni Lentini ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Sodium Channels ◽  
Frog Skeletal Muscle ◽  
Derivatives Of

Blockade of sodium channels by bistramide A in voltage-clamped frog skeletal muscle fibres

1992 ◽  
Vol 1103 (1) ◽  
pp. 109-114 ◽  
Author(s):  
Martin-Pierre Sauviat ◽  
Danièle Gouiffes-Barbin ◽  
Eudes Ecault ◽  
Jean-Francois Verbist
Keyword(s):  
Skeletal Muscle ◽  
Sodium Channels ◽  
Muscle Fibres ◽  
Frog Skeletal Muscle ◽  
Bistramide A ◽  
Skeletal Muscle Fibres

scholarly journals Differential Effects of Voltage-Dependent Inactivation and Local Anesthetics on Kinetic Phases of Ca2+ Release in Frog Skeletal Muscle

2003 ◽  
Vol 85 (1) ◽  
pp. 245-254 ◽  
Author(s):  
Gustavo Brum ◽  
Nazira Piriz ◽  
Rafael DeArmas ◽  
Eduardo Rios ◽  
Michael Stern ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Local Anesthetics ◽  
Frog Skeletal Muscle ◽  
Differential Effects ◽  
Dependent Inactivation ◽  
Voltage Dependent

Erratum: Influence of temperature and external Ca2+ concentration upon dantrolene action on excitation–contraction coupling in frog skeletal muscle

1981 ◽  
Vol 59 (6) ◽  
pp. 607-612
Author(s):  
Toshiharu Oba
Keyword(s):  
Skeletal Muscle ◽  
Mechanism Of Action ◽  
Binding Sites ◽  
Threshold Current ◽  
Frog Skeletal Muscle ◽  
Temperature Dependent ◽  
Influence Of Temperature ◽  
Contraction Coupling ◽  
Mechanical Responses ◽  
Intracellular Stimulation

Effects of dantrolene (DAN) on electrical and mechanical responses in frog skeletal muscle were studied at various Ca2+ concentrations and temperatures to elucidate the mechanism of action of DAN. The following results were obtained. (a) Twitch tension of a DAN-injected fiber, elicited by intracellular stimulation, increased transiently and then decreased whereas extracellular DAN always depressed the tension. (b) Lowering the external Ca2+ concentration resulted in the potentiation of twitch tension. The addition of DAN, however, reduced the tension significantly (p < 0.05). (c) Extracellular DAN caused a transient reduction and subsequent elevation of the threshold current; however intracellular DAN caused only elevation of threshold. (d) DAN prevented the slow depolarization of the membrane in low Ca2+ medium. (e) These effects of the drug were temperature dependent, the effect being more pronounced at higher temperatures. These findings suggest that DAN may manifest its effects by replacement of Ca2+ from its binding sites on the membrane and that this occupation of the Ca2+ sites by DAN is temperature dependent.

Influence of temperature and external Ca2+ concentration upon dantrolene action on excitation–contraction coupling in frog skeletal muscle

1981 ◽  
Vol 59 (4) ◽  
pp. 358-363 ◽  
Author(s):  
Toshiharu Oba
Keyword(s):  
Skeletal Muscle ◽  
Mechanism Of Action ◽  
Binding Sites ◽  
Threshold Current ◽  
Frog Skeletal Muscle ◽  
Temperature Dependent ◽  
Influence Of Temperature ◽  
Contraction Coupling ◽  
Mechanical Responses ◽  
Intracellular Stimulation

Effects of dantrolene (DAN) on electrical and mechanical responses in frog skeletal muscle were studied at various Ca2+ concentrations and temperatures to elucidate the mechanism of action of DAN. The following results were obtained. (a) Twitch tension of a DAN-injected fiber, elicited by intracellular stimulation, increased transiently and then decreased whereas extracellular DAN always depressed the tension. (b) Lowering the external Ca2+ concentration resulted in the potentiation of twitch tension. The addition of DAN, however, reduced the tension significantly (p < 0.05). (c) Extracellular DAN caused a transient reduction and subsequent elevation of the threshold current; however intracellular DAN caused only elevation of threshold. (d) DAN prevented the slow depolarization of the membrane in low Ca2+ medium. (e) These effects of the drug were temperature dependent, the effect being more pronounced at higher temperatures. These findings suggest that DAN may manifest its effects by replacement of Ca2+ from its binding sites on the membrane and that this occupation of the Ca2+ sites by DAN is temperature dependent.

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