Capacitance changes in frog skin caused by theophylline and antidiuretic hormone

Cuthbert, A. W.; Painter, Elisabeth

doi:10.1111/j.1476-5381.1969.tb09549.x

Cited by 6 publications

(3 citation statements)

References 18 publications

(15 reference statements)

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“…Teorell [24] and Cuthbert and Painter [5,6] determined the parameters of the network from an approximate reconstruction of the frequency response by Fourier analysis [1], and a similar procedure was used here. Calculations were carried out with the aid of the University of Liverpool's (5) and (6) became zero.…”

Section: Analysis Ofmentioning

confidence: 99%

“…In these experiments, therefore, the capacitance was determined from the response of the p.d. across the skin to the passage of a step of current [5,6,24] which can be measured much more quickly.…”

Section: Measurement Of Capacitancementioning

confidence: 99%

“…Fourier analysis of a series of values spaced at intervals of A t over a total length of time T gives values in the frequency domain at frequencies spaced at intervals of I/T, ranging from 1/T to 1/2A t. These fundamental limitations do not appear explicitly in the type of analysis used here; any value off can be substituted into Eqs. (5) and (6) and the impedance at this frequency calculated. However, this does not necessarily produce useful results.…”

Section: Analysis Ofmentioning

confidence: 99%

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Aldosterone-induced moulting in amphibian skin and its effect on electrical capacitance

Smith

1975

J. Membrain Biol.

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The resistance and capacitance of the isolated amphibian skin have been determined from measurements of the response of the voltage across the skin to small steps to current. Previous work indicates that the electrical impedance of frog skin, when the skin is bathed with Ringer's solution on both sides, is largely determined by the properties of the functional outward-facing membrane of the skin, the outer membrane of the stratum granulosum (P.G. Smith, 1971, Acta Physiol. Scand. 81:355). This membrane can be represented by a resistance and capacitance in parallel. Aldosterone, which induces conversion of the s. granulosum into a cornified cell layer and transformation of the cell layer below into a new s. granulosum, also causes a transient rise in resistance and a short-lived decrease in capacitance to about one-half its initial value. It is suggested that these electrical changes are caused by the transitory presence of two functional outward-facing membranes in series. The method of determining resistance and capacitance from the voltage response is discussed in the Appendix.

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Section: Analysis Ofmentioning

confidence: 99%

Section: Measurement Of Capacitancementioning

confidence: 99%

Section: Analysis Ofmentioning

confidence: 99%

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Aldosterone-induced moulting in amphibian skin and its effect on electrical capacitance

Smith

1975

J. Membrain Biol.

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Na+ transport by rabbit urinary bladder, a tight epithelium

1976

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By in vitro experiments on rabbit bladder, we reassessed the traditional view that mammalian urinary bladder lacks ion transport mechanisms. Since the ratio of actual-to-nominal membrane area in folded epithelia is variable and hard to estimate, we normalized membrane properties to apical membrane capacitance rather than to nominal area (probably 1 muF approximately 1 cm2 actual area). A new mounting technique that virtually eliminates edge damage yielded resistances up to 78,000 omega muF for rabbit bladder, and resistances for amphibian skin and bladder much higher than those usually reported. This technique made it possible to observe a transport-related conductance pathway, and a close correlation between transepithelial conductance (G) and short-circuit current (Isc) in these tight epithelia. G and Isc were increased by mucosal (Na+) [Isc approximately 0 when (Na+) approximately 0], aldosterone, serosal (HCO-3) and high mucosal (H+); were decreased by amiloride, mucosal (Ca++), ouabain, metabolic inhibitors and serosal (H+); and were unaffected by (Cl-) and little affected by antidiuretic hormone (ADH). Physiological variation in the rabbits' dietary Na+ intake caused variations in bladder G and Isc similar to those caused by the expected in vivo changes in aldosterone levels. The relation between G and Isc was the same whether defined by diet changes, natural variation among individual rabbits, or most of the above agents. A method was developed for separately resolving conductances of junctions, basolateral cell membrane, and apical cell membrane from this G--Isc relation. Net Na+ flux equalled Isc. Net Cl- flux was zero on short circuit and equalled only 25% of net Na+ flux in open circuit. Bladder membrane fragments contained a Na+-K+-activated, ouabain-inhibited ATPase. The physiological significance of Na+ absorption against steep gradients in rabbit bladder may be to maintain kidney-generated ion gradients during bladder storage of urine, especially when the animal is Na+-depleted.

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The role of sodium-channel density in the natriferic response of the toad urinary bladder to an antidiuretic hormone

et al. 1982

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Urinary bladders of Bufo marinus were depolarized, by raising the serosal K concentration, to facilitate voltage-clamping of the apical membrane. Passive Na transport across the apical membrane was then studied with near-instantaneous current-voltage curves obtained before and after eliciting a natriferic response with oxytocin. Fitting with the constant-field equation showed that the natriferic effect is accounted for by an increase in the apical Na permeability. It is accompanied by a small increase in cellular Na activity. Furthermore, fluctuation analysis of the amiloride-induced shot-noise component of the short-circuit current indicated that the permeability increase is not due to increased Na translocation through those Na channels which were already conducting prior to hormonal stimulation. Rather, the natriferic effects is found to be based on an increase in the population of transporting channels. It appears that, in response to the hormone, Na channels are rapidly "recruited" from a pool of electrically silent channels.

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Capacitance changes in frog skin caused by theophylline and antidiuretic hormone

Cited by 6 publications

References 18 publications

Aldosterone-induced moulting in amphibian skin and its effect on electrical capacitance

Aldosterone-induced moulting in amphibian skin and its effect on electrical capacitance

Na+ transport by rabbit urinary bladder, a tight epithelium

The role of sodium-channel density in the natriferic response of the toad urinary bladder to an antidiuretic hormone

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