Studies on the Ionic Permeability of Muscle Cells and their Models

Ling, Gilbert N.; Ochsenfeld, Margaret M.

doi:10.1016/s0006-3495(65)86752-2

Cited by 31 publications

(7 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similar microelectrode results were obtained by Hinke (54) and McLaughlin and Hinke (55). The N M R evidence supports the theoretical and experimental work of Troshin (4, 5), Ling (6)(7)(8)(9)(10)(11)(12), and Simon (13)(14)(15), and the kinetic theory of Cope (1,53). I363…”

Section: I362supporting

confidence: 83%

NMR Evidence for Complexing of Na+ in Muscle, Kidney, and Brain, and by Actomyosin. The Relation of Cellular Complexing of Na+ to Water Structure and to Transport Kinetics

Cope

1967

The Journal of General Physiology

139

View full text Add to dashboard Cite

The nuclear magnetic resonance (NMR) spectrum of Na + is suitable for qualitative and quantitative analysis of Na + in tissues. The width of the N M R spectrum is dependent upon the environment surrounding the individual Na + ion. N M R spectra of fresh muscle compared with spectra of the same samples after ashing show that approximately 70 % of total muscle Na + gives no detectable N M R spectrum. This is probably due to complexation of Na + with macromolecules, which causes the N M R spectrum to be broadened beyond detection. A similar effect has been observed when Na + interacts with ion exchange resin. N M R also indicates that about 60 % of Na + of kidney and brain is complexed. Destruction of cell structure of muscle by homogenization little alters the per cent complexing of Na +. N M R studies show that Na + is complexed by actomyosin, which may be the molecular site of complexation of some Na + in muscle. The same studies indicate that the solubility of Na + in the interstitial water of actomyosin gel is markedly reduced compared with its solubility in liquid water, which suggests that the water in the gel is organized into an icelike state by the nearby actomyosin molecules. If a major fraction of intraceUular Na + exists in a complexed state, then major revisions in most theoretical treatments of equilibria, diffusion, and transport of cellular Na + become appropriate. I N T R O D U C T I O NMost investigators have assumed t h a t the N a + of the cell was largely in free solution in intracellular water. T h e opposite conclusion was d r a w n f r o m the application of a kinetic theory of Cope (1) to V a n der Kloot's d a t a (2) on N a +

show abstract

Section: I362supporting

confidence: 83%

NMR Evidence for Complexing of Na+ in Muscle, Kidney, and Brain, and by Actomyosin. The Relation of Cellular Complexing of Na+ to Water Structure and to Transport Kinetics

Cope

1967

The Journal of General Physiology

139

View full text Add to dashboard Cite

show abstract

“…The most satisfactory explana-tion for these results is the binding model proposed by Hagiwara (1975). The surface of the membrane probably has negative fixed charges (Ling & Ochsenfeld, 1965), and with increasing external divalent cation concentrations, the cations are absorbed at this surface and form a compact electric double layer. The surface charge of the membrane, thus neutralized by the occupying divalent cations, requires more positive potential to activate ICa, and at the same time, these cations occupy the binding site for Ca2 .…”

Section: Discussionmentioning

confidence: 99%

ACTIONS OF VERAPAMIL, DILTIAZEM AND OTHER DIVALENT CATIONS ON THE CALCIUM‐CURRENT OF Helix NEURONES

Akaike

Brown

Nishi

et al. 1981

British J Pharmacology

View full text Add to dashboard Cite

1 Effects of organic verapamil and diltiazem, and cations, Ni2+, Mn2+, Co2+ and La3`on Ca2+ current (ICa) separated from other ionic currents in a Helix neurone were studied. A suction pipette technique which allows internal perfusion of the cell body and voltage clamp was used.2 Verapamil and diltiazem (10-6 10-4M) increased the threshold, and decreased both the amplitude and rate of rise of the soma Ca2+-spike. Both agents inhibited ICa over the entire range of the current-voltage (I-V) relationship dose-dependently, without shifting the threshold of the I-V relationship. Increases in external Ca2+ overcame the inhibitory action of the agents. 3 Divalent cations, Ni2+, Mn2+, Co2+ and the trivalent cation, La3+ inhibited ICa dosedependently, but induced shifts of the I-V relationship to more positive voltages. The order of potency of inhibition of ICa among these cations was as follows; Ni2+ > La3+ > Mn2+ > Co2+. 4 Double reciprocal plots for peak ICa versus external Ca2+ concentrations in the presence or absence of both organic and inorganic Ca2+-antagonists intersect at the ordinate. Results indicate that both organic and inorganic Ca2+-antagonists compete for Ca2+ at the common binding site for Ca2+.5 Internal application of the organic Ca2+-antagonists (10-4M) inhibited ICa in a time-dependent manner to about 40-60% of the control. Ni2+, when applied internally, also depressed ICa* 6 The results provide evidence that organic Ca2+-antagonists occupy the binding site for Ca2+ in a competitive manner at the surface of the soma membrane of the Helix neurone, while divalent and trivalent cations, in addition to inhibiting ICa in a similar manner to the organic Ca2+_antagonists, change the surface charge of the soma membrane.

show abstract

“…1 and Table 2), d (A 7 j) is always zero since the two phase boundary potentials cancel each other and the diffusion component is also zero. There are in the literature evidences in favor of this possibility, which suggest that the counterions behave as being mostly adsorbed to the polyelectrolyte matrix [3,13]. 1, 37 and 40 mV per decade, respectively, for 100 and 2000 mmolal microelectrodes, may indicate that the resin is not perfectly cation permselective [9].…”

Section: Resultsmentioning

confidence: 99%

Biological and artificial ion exchangers: Electrical measurements with glass microelectrodes

1978

J. Membrain Biol.

View full text Add to dashboard Cite

Biological (stratum corneum) and artificial (cation-exchange resin beads, Bio-Rad AG 50W-X2) ion exchangers were impaled by glass microelectrodes filled with KCl solution. The electrical potential difference recorded in these structures in reference to the external bathing medium was shown to be dependent on the KCl concentration of both the external and the microelectrode filling solutions. The potentials were interpreted on the grounds of the fixed charge theory of membrane potentials as a consequence of two phase boundary potentials (Donnan potentials), one at the matrix-external solution interface and the other at the matrix-microelectrode solution interface. The contribution of a diffusion component for the recorded potential was considered.

show abstract

Studies on the Ionic Permeability of Muscle Cells and their Models

Cited by 31 publications

References 18 publications

NMR Evidence for Complexing of Na+ in Muscle, Kidney, and Brain, and by Actomyosin. The Relation of Cellular Complexing of Na+ to Water Structure and to Transport Kinetics

NMR Evidence for Complexing of Na+ in Muscle, Kidney, and Brain, and by Actomyosin. The Relation of Cellular Complexing of Na+ to Water Structure and to Transport Kinetics

ACTIONS OF VERAPAMIL, DILTIAZEM AND OTHER DIVALENT CATIONS ON THE CALCIUM‐CURRENT OF Helix NEURONES

Biological and artificial ion exchangers: Electrical measurements with glass microelectrodes

Contact Info

Product

Resources

About