Osmotic Properties of Living Cells

Dick, D. A. T.

doi:10.1016/s0074-7696(08)62736-9

Cited by 125 publications

(50 citation statements)

References 170 publications

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“…Hoff s law. This relationship has been described for living cells by the equation: P( V -b) = k, where P is the osmotic pressure, V is the total cell volume, b is the nonsolvent volume of the cell, and k is a constant characteristic of the cell (Dick, 1959). The linear relationship between cell volume of the outer hair cells and osmotic pressure indicates that they follow this law.…”

Section: Discussionmentioning

confidence: 99%

Increasing intracellular free calcium induces circumferential contractions in isolated cochlear outer hair cells

1990

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The relationship between intracellular free calcium and the motile responses of outer hair cells isolated from the guinea pig cochlea was examined. Calcium levels were modulated by the addition of the calcium ionophores ionomycin or A23187 to the incubation medium and monitored with the fluorescent calcium indicator fluo-3. In the presence of 1.25 mM external calcium, the application of either ionophore (10 microM) led to an increase in intracellular free calcium from 157 +/- 76 nM to 1200 +/- 500 nM within 30–60 sec. Concurrently, cells elongated by 1–2 microns, cell diameter decreased, and cell volume shrank by 269 +/- 220 microns 3 (5.0 +/- 4.1%). The reduction in diameter was most pronounced in the middle portion of the cell (4.4% +/- 4.2%), also evident in the apical region (3.1% +/- 4.8%) but not significant in the basal region near the nucleus. This response was observed in outer hair cells from basal and apical turns of the cochlea and was reversed when the cells were rinsed with calcium-free medium supplemented with 2 mM EGTA. Optical imaging of the cell membrane with the potentiometric dye 1-(3- sulfonatopropyl)-4-[beta] [2-(di-n-butylaminol)-6-naphthyl vinyl] pyridinium betaine during the elevation of intracellular calcium demonstrated features of contractility at the lateral cell membrane. A rise in intracellular calcium as well as the motile response was still observed after a 5-min exposure of the cells to a calcium-free solution (supplemented with 2 mM EGTA), indicating that the ionophore was also able to liberate calcium from intracellular sites. However, depletion of calcium stores through prolonged incubation of the cells in calcium- free medium (30–60 min) suppressed both the calcium signal and the cell response. The calmodulin inhibitors trifluoperazine and pimozide (30 microM) blocked the cell motility induced by ionomycin while they left the increase of intracellular calcium unaffected. These observations suggest that calcium-dependent circumferential contractions in outer hair cells are mediated by calmodulin. The application to the extracellular medium of putative neurotransmitters of the cochlear efferent system such as acetylcholine and GABA led to neither an increase in intracellular calcium nor a modification of cell shape. Therefore, these neurotransmitters may not be directly involved in calcium-induced contractions in outer hair cells. The circumferential contractions altered the stiffness of the plasma membrane and the turgor of the cell. Under normal conditions, changes in cell volume were inversely proportional to the osmotic pressure of the extracellular medium following van't Hoff's law.(ABSTRACT TRUNCATED AT 400 WORDS)

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Section: Discussionmentioning

confidence: 99%

Increasing intracellular free calcium induces circumferential contractions in isolated cochlear outer hair cells

1990

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“…This mechanism of hemolysis was described in 1936 by Davson (8) and was termed colloid-osmotic hemolysis by Wilbrandt in 1941 (9). Recently, Dick has summarized the topic clearly (10). An analogous system has been demonstrated by Goldberg, Green, Barrow, and Fleischer (11)(12)(13) in their studies of the lysis of Krebs ascites tumor cells by rabbit antibody and C'.…”

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confidence: 93%

Differences in the Mechanism of In Vitro Immune Hemolysis Related to Antibody Specificity*

Sears¹,

Weed²,

Swisher³

1964

J. Clin. Invest.

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“…It would be valuable to know something about the behaviour of the soluble muscle proteins in this respect, because although these substances can normally be responsible for only a very small portion of the osmotic pressure of the sarcoplasm, the osmotic coefficients of many proteins are known to increase markedly with concentration (see Dick, 1959;McConaghey & Maizels, 1961).…”

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confidence: 99%

“…The estimated aqueous fraction of the cell (80 %) thus exceeds the apparent solvent volume (67 %) by about 13 % of the volume of the fibre. Discrepancies of this sort have been observed in other types of cells, notably the erythrocyte, and have prompted various interpretations (see Dick, 1959), most of them variations on one of three basic ideas: (1) an appreciable part of the fibre water is bound to some cellular constituent in such a way that it is not free to participate in the osmotic adjustments of the cell; (2) the osmotic coefficients of certain cytoplasmic solutes increase enough with increasing concentration to account for the discrepancy; (3) the contents of the cell have enough mechanical rigidity to oppose osmotically induced volume changes. As Dick has pointed out, it is of questionable meaning to try to distinguish among these interpretations in the case of a homogeneous system, since at the present state of knowledge each 'explanation' amounts in reality to little more than a restatement of the fact that the system does not behave like an ideal solution.…”

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confidence: 99%

Influence of osmotic strength on cross‐section and volume of isolated single muscle fibres

Blinks¹

1965

The Journal of Physiology

227

220

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Despite long-continued interest in the subject, uncertainty still exists about some fundamental aspects of the osmotic behaviour of striated muscle cells. One unsettled problem has to do with the extent to which the fibre adjusts its volume in response to changes in the osmotic pressure of the bathing medium. There is abundant evidence, both from indirect observations and from direct measurements of volume, that under conditions in which one might expect the transfer of solutes across the cell membrane to be slight and over a moderate range of osmotic strengths, the striated muscle fibre exhibits ideal or nearly ideal osmotic behaviour (in the sense that it behaves as a freely distensible semipermeable bag containing a fixed amount of solute and a certain amount of solid or osmotically inactive matter) (e.g. Sato, 1954a; Dydynska & Wilkie, 1963;Reuben, Lopez, Brandt & Grundfest, 1963). However, recent studies in which changes in fibre volume were estimated from measurements of the widths of single muscle fibres have suggested departures from ideal behaviour at very high and very low osmotic strengths. Dydynska & Wilkie (1963) found that the widths of fibres in the sternocutaneus muscle of the frog did not decrease as much as would have been expected when the muscle was placed in solutions whose osmotic strength had been made more than twice normal by the addition of sucrose. This finding was in contrast with the results of their chemical estimates of fibre water in the sartorius muscle, which indicated that the muscle fibres exhibited ideal osmotic behaviour up to osmotic strengths at least four times that of the normal bathing solution. Reuben et al. (1963) estimated changes in the volume of isolated single fibres of the semitendinosus muscle of the frog, and found that the fibres appeared to swell less than might have been expected when the osmotic strength of the bathing solution was reduced by more than half. This finding is in qualitative agreement with the results of some chemical estimates of fibre water made on whole muscles by Grieve

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Osmotic Properties of Living Cells

Cited by 125 publications

References 170 publications

Increasing intracellular free calcium induces circumferential contractions in isolated cochlear outer hair cells

Increasing intracellular free calcium induces circumferential contractions in isolated cochlear outer hair cells

Differences in the Mechanism of In Vitro Immune Hemolysis Related to Antibody Specificity*

Influence of osmotic strength on cross‐section and volume of isolated single muscle fibres

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