A comparison of the effects of cationic, anionic, and neutral amphipathic agents on the contractile behaviour of frog skeletal muscle. II. Amplitude of depolarization and repolarization-induced contractures

1984 ◽  
Vol 62 (12) ◽  
pp. 1356-1364
Author(s):  
James G. Foulks ◽  
Lillian Morishita
Keyword(s):  
Skeletal Muscle ◽  
Hydrophobic Interactions ◽  
Contractile Function ◽  
Divalent Cations ◽  
Partial Restoration ◽  
Alkyl Sulfonates ◽  
Hydrocarbon Chains ◽  
Alkyl Sulfonate ◽  
The Difference ◽  
High Concentrations

Sufficiently high concentrations of cationic (n-alkyl trimethylammonium) or neutral (n-alkanols) amphipathic agents reduced the amplitude of maximum K contractures of frog toe muscles, an effect which was antagonized by reduced temperature, by the presence of perchlorate anions, or (to a lesser extent) by an increased concentration of divalent cations. Enhancement of the similar effect of tetracaine was prominent only with alkyl trimethylammonium compounds. Enhancement of the depressant effect of acidity (pH 5.0) was observed with octyl trimethylammonium and octanol but not with octanesulfonate or butanol. Partial restoration of potassium contractures in media lacking divalent cations was produced by octane- or nonane-sulfonate and by propanol but not by octyl trimethylammonium or octanol. The alkyl sulfonates differed from the other agents studied in producing tonic contractures at concentration which did not reduce maximum K-contracture tension. The alkyl sulfonates also differed from other amphipaths of similar size in their ability to elicit small repolarization-induced contractures in the absence of perchlorate, although this property also was shared by small alkanols. Sufficient concentrations of all amphipaths reduced the amplitude of repolarization-induced contractures in the presence of perchlorate. The intensity of the effects of these agents on contractile function usually was proportional to the size of their apolar group, and with ionic apmphipaths such effects were apparent only with compounds having hydrocarbon chains containing eight or more carbon atoms. These experiments indicate that hydrophobic interactions in the external lamina of the sarcolemma can influence the potential-dependent control of contractile function in skeletal muscle, presumably by effects on the conformational transitions of integral membrane proteins. The similarity between many of the effects of alkyl sulfonate and small n-alkanols as well as those of small concentrations of perchlorate suggest that chaotropic actions can contribute to these effects. The difference between the effects of anionic and cationic agents, as well as between the effects of n-alkanols of different size may be attributable to the different intensity of similar effects at different membrane sites.

A comparison of the effects of cationic, anionic, and neutral amphipathic agents on the contractile behaviour of frog skeletal muscle. I. Twitches and potential threshold for contraction

1984 ◽  
Vol 62 (12) ◽  
pp. 1348-1355
Author(s):  
James G. Foulks ◽  
Lillian Morishita
Keyword(s):  
Skeletal Muscle ◽  
Hydrophobic Interactions ◽  
Contractile Function ◽  
Divalent Cations ◽  
Frog Skeletal Muscle ◽  
Twitch Potentiation ◽  
Low Concentrations ◽  
Small N ◽  
Potential Threshold ◽  
Caffeine Contractures

Cationic, anionic, and neutral amphipathic agents displayed striking differences as well as similarities in their effects on the contractile function of frog skeletal muscle. Slowed repolarization during the action potential appeared to account for twitch potentiation by low concentrations of alkyl trimethylammonium and by small n-alkanols (propanol, butanol). Small n-alkanols also caused a decrease in the potential threshold for K contractures and slower relaxation of submaximum K contractures as well as enhancement of chloride withdrawal and caffeine contractures, but these effects were not observed with larger alkanols. For the ionic amphipathic agents, the direction of the changes in the relation between K0 and K-contracture tension could be accounted for on the basis of the expected changes in surface charge, but the effects of these two types of agents on the rate of relaxation of submaximum K contractures were disproportionate and with the cationic series were opposite in direction to those produced by inorganic divalent cations. The reductions in the amplitude of chloride-withdrawal contractures by cationic as well as anionic amphipaths indicated that both types of agents can impair excitation–contraction coupling. Similar depressant effects on caffeine contractures demonstrate that these responses also can be influenced by events restricted to the external lamina of the sarcolemma. It is concluded that opposite effects can be produced by similar perturbations in different regions of the sarcolemma and that electrostatic as well as hydrophobic interactions can make an important contribution to the effects of amphipathic agents on twitches and contractures in skeletal muscle.

The influence of D2O, perchlorate, and variation in temperature on the potential-dependent contractile function of frog skeletal muscle

1985 ◽  
Vol 63 (6) ◽  
pp. 693-703
Author(s):  
James G. Foulks ◽  
Lillian Morishita
Keyword(s):  
Skeletal Muscle ◽  
Contractile Function ◽  
Divalent Cations ◽  
Conformational Transitions ◽  
The Other ◽  
Frog Skeletal Muscle ◽  
Solvent Structure ◽  
Opposing Effects ◽  
Kinetics Of ◽  
Reduced Temperature

D2O and perchlorate manifest opposing effects on the contractile function of skeletal muscle (amplitude of twitches and maximum K contractures, potential dependence of contraction activation and inactivation), and when combined the influence of one may effectively antagonize that of the other. The ratio of perchlorate concentrations required to produce effects of equal intensity (e.g., twitch enhancement and restoration of maximum K contractures in media lacking divalent cations or containing a depressant concentration of a cationic amphipath) in H2O and D2O solutions was generally rather constant. These findings are compatible with the view that both agents can influence contractile function by virtue of their effects on solvent structure. In the absence of divalent cations, the effects of reduced temperature resemble those of D2O whereas the effects of increased temperature resemble those of the chaotropic anion. However, in other media, variation in temperature was found to result in additional nonsolvent effects so that low temperature could oppose rather than enhance the effects of D2O. These observations are discussed in terms of a model which postulates a role for solvent influences on the kinetics of two separate potential-dependent conformational transitions of membrane proteins which mediate the activation and inactivation of contraction in skeletal muscle.

Some effects of organic anions on excitability and excitation–contraction coupling in frog skeletal muscle

1977 ◽  
Vol 55 (3) ◽  
pp. 700-708 ◽  
Author(s):  
J. G. Foulks ◽  
Florence A. Perry
Keyword(s):  
Skeletal Muscle ◽  
Divalent Cations ◽  
Membrane Surface ◽  
Organic Anions ◽  
Polar Group ◽  
Frog Skeletal Muscle ◽  
Excitation Contraction Coupling ◽  
Partial Restoration ◽  
Contraction Coupling ◽  
Contractile Performance

When substituted for external chloride, organic anions differed markedly from one another in the extent to which they produced hyperexcitability and in the direction and intensity of their effects on twitch tension in frog skeletal muscle. All of the anions studied reduced the threshold [K]0 for K contractures and most enhanced twitch tension. Among carboxylate anions, increasing the size of the attached apolar hydrocarbon chain led to decreased hyperexcitability and to reduction in the amplitude of twitches and maximum K-contractures, butyrate being the most effective depressant of these responses. Sulfonate anions produced much less conspicuous changes in contractile performance. With γ-hydroxybutyrate, the introduction of a polar group on the hydrocarbon terminus resulted in twitch enhancement and partial restoration of maximum K-contracture tension. The depressant effect of butyrate on K contractures was partially overcome by a fivefold increase in the external concentration of calcium but twitches were unaffected. Perchlorate (12 mM) effectively antagonized the depressant actions of butyrate on twitches as well as K contractures. Most of the effects of these anions were prompt in onset. Impairment of contractile performance by butyrate was not accompanied by appreciable changes in membrane resting or action potentials or in the relation between [K]0 and membrane potential, and took place in spite of reduction in K-contracture threshold. Such effects must result from alteration in excitation–contraction coupling, possibly by interference with the binding of divalent cations to the membrane surface.

Restoration of the Ability of Frog Skeletal Muscle to Develop Potassium Contractures in Calcium-Deficient Media

1973 ◽  
Vol 51 (5) ◽  
pp. 335-343 ◽  
Author(s):  
J. G. Foulks ◽  
J. A. D. Miller ◽  
Florence A. Perry
Keyword(s):  
Skeletal Muscle ◽  
Contractile Function ◽  
Divalent Cations ◽  
Frog Skeletal Muscle ◽  
Free Media ◽  
Dependent Processes

A number of agents were tested for their ability to restore potassium (K) contractures in calcium-free media. Effective agents included caffeine, chloroform, more polar permeant anions (e.g. nitrate and perchlorate) in place of external chloride, as well as divalent cations, e.g. Mg2+. The presence of sufficient EGTA to preclude significant increases in [Ca]0 did not affect the extent of K contracture restoration produced by these agents. The loss of K contracture capacity in calcium-free media, and its restoration by effective agents, appear to be related to the disproportionate effect of these procedures on the relation between log [K]0 and the potential-dependent processes which regulate contractile function.

scholarly journals Evidence for a cytochrome bcc–aa 3 interaction in the respiratory chain of Mycobacterium smegmatis

Microbiology ◽  
2006 ◽  
Vol 152 (3) ◽  
pp. 823-829 ◽  
Author(s):  
James A. Megehee ◽  
Jonathan P. Hosler ◽  
Michael D. Lundrigan
Keyword(s):  
Electron Transfer ◽  
Respiratory Chain ◽  
Mycobacterium Smegmatis ◽  
Spectroscopic Analysis ◽  
Hydrophobic Interactions ◽  
Divalent Cations ◽  
Ionic Interactions ◽  
Respiratory Pathway ◽  
Binding Residues ◽  
High Concentrations

Spectroscopic analysis of membranes isolated from Mycobacterium smegmatis, along with analysis of its genome, indicates that the cytochrome c branch of its respiratory pathway consists of a modified bc 1 complex that contains two cytochromes c in its c 1 subunit, similar to other acid-fast bacteria, and an aa 3-type cytochrome c oxidase. A functional association of the cytochrome bcc and aa 3 complexes was indicated by the findings that levels of detergent sufficient to completely disrupt isolated membranes failed to inhibit quinol-driven O2 reduction, but known inhibitors of the bc 1 complex did inhibit quinol-driven O2 reduction. The gene for subunit II of the aa 3-type oxidase indicates the presence of additional charged residues in a predicted extramembrane domain, which could mediate an intercomplex association. However, high concentrations of monovalent salts had no effect on O2 reduction, suggesting that ionic interactions between extramembrane domains do not play the major role in stabilizing the bcc–aa 3 interaction. Divalent cations did inhibit electron transfer, likely by distorting the electron-transfer interface between cytochrome c 1 and subunit II. Soluble cytochrome c cannot donate electrons to the aa 3-type oxidase, even though key cytochrome c-binding residues are conserved, probably because the additional residues of subunit II prevent the binding of soluble cytochrome c. The results indicate that hydrophobic interactions are the primary forces maintaining the bcc–aa 3 interaction, but ionic interactions may assist in aligning the two complexes for efficient electron transfer.

Effect of External Calcium and other Divalent Cations on K+ Contractures in Denervated Slow Skeletal Muscle Fibers of the Frog

2019 ◽  
Author(s):  
Leonardo Hernández
Keyword(s):  
Skeletal Muscle ◽  
Binding Capacity ◽  
Divalent Cations ◽  
Muscle Fibers ◽  
Free Calcium ◽  
Slow Skeletal Muscle ◽  
Skeletal Muscle Fibers ◽  
Free Calcium Concentration ◽  
Chronic Denervation ◽  
Denervated Muscles

The influence of Ca2+ and other divalent cations on contractile responses of slow skeletal muscle fibers of the frog (Rana pipiens) under conditions of chronic denervation was investigated.Isometric tension was recorded from slow bundles of normal and denervated cruralis muscle in normal solution and in solutions with free calcium concentration solution or in solutions where other divalent cations (Sr2+, Ni2+, Co2+ or Mn2+) substituted for calcium. In the second week after nerve section, in Ca2+-free solutions, we observed that contractures (evoked from 40 to 80 mM-K+) of non-denervated muscles showed significantly higher tensions (p<0.05), than those from denervated bundles. Likewise, in solutions where calcium was substituted by all divalent cations tested, with exception of Mn2+, the denervated bundles displayed lower tension than non-denervated, also in the second week of denervation. In this case, the Ca2+ substitution by Sr2+ caused the higher decrease in tension, followed by Co2+ and Ni2+, which were different to non-denervated bundles, as the lowest tension was developed by Mn2+, followed by Co2+, and then Ni2+ and Sr2+. After the third week, we observed a recovery in tension. These results suggest that denervation altering the binding capacity to divalent cations of the voltage sensor.

The metachor as a characteristic of the association of electrolytes in aqueous solutions

1984 ◽  
Vol 49 (5) ◽  
pp. 1061-1078 ◽  
Author(s):  
Jiří Čeleda ◽  
Stanislav Škramovský
Keyword(s):  
Aqueous Solutions ◽  
Apparent Volume ◽  
Solutions Of Electrolytes ◽  
Molal Volumes ◽  
The Difference ◽  
High Concentrations ◽  
Experimental Values ◽  
Suitable Characteristic ◽  
Association Of Ions ◽  
Very High

Based on the earlier paper introducing a concept of the apparent parachor of a solute in the solution, we have eliminated in the present work algebraically the effect which is introduced into this quantity by the additivity of the apparent molal volumes. The difference remaining from the apparent parachor after substracting the contribution corresponding to the apparent volume ( for which the present authors suggest the name metachor) was evaluated from the experimental values of the surface tension of aqueous solutions for a set of 1,1-, 1,2- and 2,1-valent electrolytes. This difference showed to be independent of concentration up to the very high values of the order of units mol dm-3 but it was directly proportional to the number of the free charges (with a proportionality factor 5 ± 1 cm3 mol-1 identical for all studied electrolytes). The metachor can be, for this reason, a suitable characteristic for detection of the association of ions and formation of complexes in the solutions of electrolytes, up to high concentrations where other methods are failing.

Effects ofS-nitroso-N-acetylcysteine on contractile function of reperfused skeletal muscle

1998 ◽  
Vol 274 (3) ◽  
pp. R822-R829 ◽  
Author(s):  
Long-En Chen ◽  
Anthony V. Seaber ◽  
Rima M. Nasser ◽  
Jonathan S. Stamler ◽  
James R. Urbaniak
Keyword(s):  
Skeletal Muscle ◽  
Reperfusion Injury ◽  
Contractile Function ◽  
Ischemia Reperfusion ◽  
Protective Role ◽  
Control Group ◽  
Group Vi ◽  
No Donor ◽  
Early Reperfusion ◽  
Reconstructive Operations

The ultimate goal of replantation and microsurgical reconstructive operations is to regain or improve impaired function of the tissue. However, the data related to the influence of NO on tissue function are limited. This study evaluated the effects of the NO donor S-nitroso- N-acetylcysteine (SNAC) on contractile function of skeletal muscle during reperfusion. Forty-nine rats were divided into six groups. The extensor digitorum longus (EDL) muscles in groups I and II were not subjected to ischemia-reperfusion but were treated with a low (100 nmol/min) or high (1 μmol/min) dose of SNAC. In groups III- V, the EDL underwent 3 h of ischemia and 3 h of reperfusion and was also treated with low (100 nmol/min) or high doses (1 or 5 μmol/min) of SNAC. Group VI was a phosphate-buffered saline (PBS)-treated control group. Twenty additional animals were used to document systemic effects of SNAC and PBS only. SNAC or PBS was infused for 6.5 h, beginning 30 min before ischemia and continuing throughout the duration of reperfusion. Contractile testing compared the maximal twitch force, isometric tetanic contractile forces, fatigue, and fatigue half time of the experimental EDL and the contralateral nontreated EDL. The findings indicate that 1) SNAC does not influence contractile function of EDL muscle not subjected to ischemia-reperfusion, 2) SNAC significantly protects the contractile function of ischemic skeletal muscle against reperfusion injury in the early reperfusion period, and 3) the protective role of SNAC is critically dosage dependent; protection is lost at higher doses. The conclusion from this study is that supplementation with exogenous NO exerts a protective effect on the tissue against reperfusion injury.

scholarly journals Relationship between Serum Alkaline Phosphatase and Low Muscle Mass Index Among Korean Adults: A Nationwide Population-Based Study

Biomolecules ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 842
Author(s):  
Jun-Hyuk Lee ◽  
A-Ra Cho ◽  
Yong-Jae Lee
Keyword(s):  
Skeletal Muscle ◽  
Alkaline Phosphatase ◽  
Muscle Mass ◽  
Skeletal Muscle Mass ◽  
Serum Alkaline Phosphatase ◽  
Inflammatory Marker ◽  
Characteristic Curve ◽  
Population Based ◽  
Nutrition Survey ◽  
The Difference

Sarcopenia has attracted interest due to its impact on various health problems. Chronic inflammation is an important contributor to sarcopenia. Thus, we aimed to investigate the association between serum alkaline phosphatase (ALP), which is a novel inflammatory marker, and muscle mass. This study included 15,579 adults from the 2008–2011 Korea National Health and Nutrition Survey. Low skeletal muscle mass index (LSMI) was defined as body mass index-adjusted appendicular skeletal muscle mass less than 0.789 for men and 0.512 for women. Multiple logistic regression revealed that the highest ALP tertile was significantly associated with LSMI compared with the lowest ALP tertile in both men [Odds ratio (OR): 1.41; 95% confidence interval (CI): 1.04–1.91] and women (OR: 1.45; 95% CI: 1.00–2.10) after adjusting for other confounders. On the receiver operating characteristic curve analysis, the predictive power was significantly higher for ALP levels than for white blood cell count in women (p < 0.001), whereas the difference was not significant in men (p = 0.515). Our findings suggest the potential use of serum ALP as an inflammatory marker and a predictor of sarcopenia.

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