Abstract
The membrane potentials of posterior fibers of the isolated American bullfrog lens were measured in Ringer solution containing various external Ca2+ concentrations ([Ca]0) by using a conventional glass microelectrode technique. The reduction or removal of [Ca]0 evoked a rapid depolarization of the lens potential whereas the increase of [Ca]0 had almost no effects on the membrane potential. The magnitude of depolarization in Ca2+-free medium was augmented by adding veratrine but reduced by either the addition of tetrodotoxin (TTX) or the reduction of external Na+ concentration. A slight depolarization still remained after the blockade of Na-channels by adding TTX and developed progressively during a successive exposure of lens to Ca2+-free media. It was concluded that veratrine-sensitive rapid an large depolarization in the frog lens fibers bathed in Ca2+-free medium results from a marked elevation of Na+ permeability but that the TTX-insensitive time-dependent depolarization may depend on the loss of K+ content in lens fibers.
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References
Akaike N (1982) Hyperpolarization of mammalian skeletal muscle fibers in K-free media. Am J Physiol 242:C12–18
Becker B, Cotlier E (1965) The efflux of 86 rubidium from the rabbit lens. Invest Ophthalmol 4:117–121
Bentley PJ, Cruz E (1978) The role of Ca2+ in maintaining the Na and K content of the amphibian lens. Exp Eye Res 27:335–341
Candia OA (1980) The influence of calcium-free media on the electrical properties of the isolated toad lens. Exp Eye Res 30:193–201
Curran PF, Gill JR (1962) The effect of calcium on sodium transport by frog skin. J Gen Physiol 45:625–641
Delamere NA, Duncan G (1977) A comparison of ion concentrations, potentials and conductances of amphibian, bovine and cephalopod lenses. J Physiol (Lond) 272:167–186
Delamere NA, Paterson CA (1978) The influence of calcium-free EGTA solution upon membrane permeability in the crystalline lens of the frog. J Gen Physiol 71:581–593
Delamere NA, Paterson CA (1979) The influence of calcium-free solution upon permeability characteristics of the rabbit lens. Exp Eye Res 28:45–53
Duncan G, Bushell AR (1975) Ion analyses of human cataractous lenses. Exp Eye Res 20:223–230
Frank GB (1958) Effect of veratrine on muscle fiber membrane and on negative after-potential. J Neurophysiol 21:263–278
Gernshfeld NL, Shanes AM (1959) The influence of high hydrostatic pressure on cocaine and veratrine action in a vertebrate nerve. J Gen Physiol 42:647–653
Goldman DE (1943) Potential, impedance and rectification in membranes. J Gen Physiol 2:37–49
Harris JE, Gehrsitz LB (1951) Significance of changes in potassiuim and sodium content of the lens. Am J Ophthalmol 34:131–138
Harris JE, Gehrsitz LB, Nordquist L (1953) The in vitro reversal of the lenticular cation shift induced by cold or calcium deficiency. Am J Ophthalmol 36:39–49
Hille B (1968) Pharmacological modifications of the sodium channels of the frog nerve. J Gen Physiol 51:199–219
Jedziniak JA, Nicoli DF, Yates EM, Benedek GB (1976) On the calcium concentration of cataractous and normal human lenses and protein fractions of cataractous lenses. Exp Eye Res 23:325–332
Johnson P, Bianchi CP (1971) The effect of veratridine on sodiumsensitive radiocalcium uptake in frog sartorius muscle. Eur J Pharmacol 16:90–99
Kimizuka J, Koketsu K (1963) Changes in the membrane permeability of frog's sartorius muscle fibers in Ca-free EGTA solution. J Gen Physiol 47:379–392
MacFarlane WW, Meares JD (1958) Chemical modification of intracellularly recorded after-potentials of frog skeletal muscle. J Physiol (Lond) 142:78–96
Merola LO, Kern HL, Kinoshita JH (1960) The effect of calcium on the cations of calf lens. Arch Ophthalmol 63:830–835
Morrill GA, Robbins E (1967) The role of calcium in the regulation of the steady-state levels of sodium and potassium in the HeLa cell. J Gen Physiol 50:781–792
Okajima Y, Akaike N (1982) Effect of ouabain, lithium and cooling on the frog lens fiber potential. Jpn J Physiol 32:45–54
Rae JL (1974) Voltage compartments in the lens. Exp Eye Res 19:235–242
Shanes AM (1952) The ultraviolet spectra and neurophysiological effect of “veratrine” alkaloids. J Pharmacol Exp Ther 105:216–231
Shanes AM (1958) Electrochemical aspects of physiological and pharmacological action in excitable cells. Pharmacol Rev 10:59–273
Spector A, Rothschild C (1973) The effect of calcium upon the reaggregation of bovine alpha crystallin. Invest Ophthalmol 12:225–231
Spector A, Adams D, Krul K (1974) Calcium and high molecular weight protein aggregates in bovine and human lens. Invest Ophthalmol 13:982–990
Sperelakis N, Pappano AJ (1969) Increase in PNa and PK of cultured heart cells produced by veratridine. J Gen Physiol 53:97–114
Taura Y, Murata T, Akaike N (1979) Topographical aspects of crystalline lens potential. Comp Biochem Physiol 63:475–480
Thoft RA, Kinoshita JH (1965) The effect of calcium on rat lens permeability. Invest Ophthalmol 4:122–218
Ulbricht W (1965) Voltage clamp studies of veratrinized frog nodes. J Cell Comp Physiol 66, Suppl 2:91–98
Witt PN, Swaine CR (1957) Studies on veratrum alkaloids. XXV. Veratrine response and antiveratrinic action in frog sartorius muscle. J Pharmacol Exp Ther 120:63–74
Yonemura K (1970) Depolarizations produced by veratrine in rat skeletal muscle fibers. Kumamoto Med J 23:41–55
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Akaike, N., Okajima, Y. Effects of veratrine and tetrodotoxin on the frog lens potential in normal and calcium-free media. Pflugers Arch. 394, 333–337 (1982). https://doi.org/10.1007/BF00583698
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DOI: https://doi.org/10.1007/BF00583698