The energetics of Cl− active transport inChara

Reid, R. J.; Walker, N. A.

doi:10.1007/bf01872530

Cited by 10 publications

(4 citation statements)

References 22 publications

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“…Over a period of 10 rain (the normal interval between pulses) a C1-influx of about 35 nmol m -2 sec -1 would replenish the amount lost during a typical inward response. This influx is large for Chara cells in the dark (Reid & Walker, 1984) but not impossible when compared with rates for C1--depleted cells (Beilby & Walker, 1981).…”

Section: Is the Inward-2 Current Punchthrough?mentioning

confidence: 96%

Inward membrane current inChara inflata: I. A voltage- and time-dependent Cl− component

1986

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Summary. An inward current which increases in magnitude over a period of seconds is activated when the membrane of Chara ir~flata (a green alga) in a K+-conductive state is hyperpolarized by a voltage clamp. The peak current and the half-time of activation are exponentially dependent on membrane potential difference. It was found by using an external CI electrode that the component exponentially dependent on potential was due to an efflux of C1-. The measured current-voltage curves and the kinetics of deactivation of the current showed that other timedependent components contributed to the net inward current. The "punchthrough" theory of Coster (Biophys. J. 5:669-686, 1965) does not adequately explain the inward current since a "punchthrough potential" could not be obtained, and the inward current was distinctly time dependent. The voltage and time dependence of the inward current strongly suggests that the C1-efflux activated by hyperpolarization is through voltage-gated channels which open more frequently as the membrane is hyperpolarized.

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Section: Is the Inward-2 Current Punchthrough?mentioning

confidence: 96%

Inward membrane current inChara inflata: I. A voltage- and time-dependent Cl− component

1986

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“…At the end of the 0.6 ksec influx period the cell was rinsed with OM for a further 0.6 ksec. Any cells whose PD "collapsed" (see Reid & Walker, 1984) during the influx period were rejected. At the end of the rinse period the cell and the reservoirs of PM were removed and counted for 36C1.…”

Section: Intracellular Perfusionmentioning

confidence: 99%

“…The perfusion method has been described previously (Reid & Walker, 1984) and is essentially the same as that used by Smith and Walker (1981) for studying electrogenic H + pumping in the Chara plasmalemma. Briefly, an internodal cell was mounted on a perspex block having three compartments.…”

Section: Intracellular Perfusionmentioning

confidence: 99%

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Control of Cl− influx inChara by internal pH

Reid

Walker

1984

J. Membrain Biol.

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Summary. The possible regulation of CI influx in Chara by the cytoplasmic C1-concentration and cytoplasmic pH was investigated using both intact and intracellularly perfused cells. In perfused cells C1-influx was sensitive to changes in the internal C1-concentration but only when the concentration was less than 1 mM.In intact cells the metabolic inhibitors, CCCP, DCMU, and oligomycin which inhibit C1-influx also reduced the cytoplasmic pH. A correlation between ATP concentration and cytoplasmic pH was shown to apply when the ATP concentration was lowered using these inhibitors. The possible relationships between ATP status, cytoplasmic pH, and C1-influx are discussed.

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