Invertebrate epithelial Na+ channels: amiloride-induced current-noise in crab gill

Zeiske, Wolfgang; Onken, Horst; Schwarz, Hans-Joachim; Graszynski, Kai

doi:10.1016/0005-2736(92)90201-v

Cited by 44 publications

(29 citation statements)

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“…Another feature of the gill epithelium of the shore crab was its sensitivity to the epithelial Na + transport blocker, the diuretic amiloride (Benos, 1982). In a dose-dependent manner, the negative I~c became more negative and Gt decreased with a halfmaximal concentration (KAMI) of about 10 gmol/1 (Onken & Siebers, 1992), which is in the currently reported range for apical Na + channels from invertebrate epithelia (Dannenmaier et al, 1991;Zeiske et al, 1992). These effects, consistent with the drug-induced inhibition of a positive I~c (probably the net inward movement of positive ions), may indicate the presence of an active and electrogenic Na+-uptake parallel to the mechanisms responsible for negative Isc, which is likely to reflect electrogenic C1-uptake.…”

Section: Carcinus Maenasmentioning

confidence: 60%

“…Internal haemolymph-like NaCl-saline, during the whole period Isc reversed. This positive Isc depended on external Na + and was highly sensitive (halfmaximal effect below 1 ~mol/1) to external amiloride (Schwarz, 1990;Zeiske et al, 1992;see Fig. 6, this paper) as well as to internal ouabain (Schwarz, 1990).…”

Section: Eriocheir Sinensis: a Model For Crabs Which Conquered Freshwmentioning

confidence: 88%

“…Only by using this method has it become possible to define ion-specific and arearelated currents and conductances in great detail: (a) unlike the PD which is a qualitative measure, quantitative parameters were obtained (Schwarz & Graszynski, 1989;Onken et al, 1991;Zeiske et al, 1992;Onken & Siebers, 1992); (b) cell impalements with microelectrodes via the basolateral membrane allowed the investigation of membrane potentials and conductances (Onken et al, 1991), and (c) application of current-noise analysis resulted in the unambiguous demonstration of Na+-channels in the apical gill membrane of the Chinese crab (Zeiske et al, 1992).…”

Section: Electrophysiological Methods In Crab Gill Investigationsmentioning

confidence: 99%

“…In the following, we focus on basic data and those results which are important to understand the proposed transport model shown in Figure 4. More detailed information, like kinetics or regulation of NaC1 uptake, can be found elsewhere (Onken, 1989;Schwarz, 1990;Onken et al, 1991;Riestenpatt et al, 1992;Zeiske et al, 1992).…”

Section: Eriocheir Sinensis: a Model For Crabs Which Conquered Freshwmentioning

confidence: 99%

“…This has become possible in the last few years by the application of modern electrophysiological techniques to isolated epithehal layers which were mounted in an Ussingchamber (Schwarz & Graszynski, 1989;Onken, 1989;Schwarz, 1990;Onken et al, 1991;Zeiske et al, 1992;Onken & Siebers, 1992).…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

How to overcome osmotic stress? Marine crabs conquer freshwater. New insights from modern electrophysiology

Onken

Graszynski

Johannsen

et al. 1995

Helgolander Meeresunters

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In the present article we review our findings on split lamella preparations of crab gills mounted in modified Ussing-chambers with respect to mechanistic and ecophysiological aspects. The leaky gill epithelium of shore crabs adapted to brackish water absorbs Na + and C1-in a coupled mode, and shows similarities to other salt-absorbing epithelia exposed to moderately diluted media. The results so far obtained for NaCI uptake across the gills of the shore crab are compatible with a transport model where two cell types operate in parallel, one displaying cotransport-like NaC1 absorption, similar to that in the thick ascending limb of Henle's loop of the mammalian mephron, and the other one with characteristics of amiloride-sensitive, channel-mediated Na + uptake by frog skin. Although there is no clear evidence for the apical mechanisms in this model, it may serve as a good basis for more detailed studies in the future. The moderately tight gill epithelium of freshwater adapted Chinese crabs absorbs Na + and C1-independently from each other, and shows similarities to other salt-absorbing epithelia exposed to freshwater. The characteristics of a positive, Na +-dependent short-circuit current with externally C1--free saline indicate that active Na + uptake proceeds in a frog-skin-like mode via apical Na+-channels and the basolateral Na+/K+opump. The nature of a negative short-circuit current with external C1--saline indicates that active and Na +-independent CI-uptake is driven by an apical V-type H~--pump and proceeds via apical C1-/ HCO3--exchange and basolateral C1--channels.

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Section: Carcinus Maenasmentioning

confidence: 60%

Section: Eriocheir Sinensis: a Model For Crabs Which Conquered Freshwmentioning

confidence: 88%

Section: Electrophysiological Methods In Crab Gill Investigationsmentioning

confidence: 99%

Section: Eriocheir Sinensis: a Model For Crabs Which Conquered Freshwmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

How to overcome osmotic stress? Marine crabs conquer freshwater. New insights from modern electrophysiology

Onken

Graszynski

Johannsen

et al. 1995

Helgolander Meeresunters

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show abstract

Osmoregulation and Excretion

Larsen

Deaton

Onken

et al. 2014

Comprehensive Physiology

179

141

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The article discusses advances in osmoregulation and excretion with emphasis on how multicellular animals in different osmotic environments regulate their milieu intérieur. Mechanisms of energy transformations in animal osmoregulation are dealt with in biophysical terms with respect to water and ion exchange across biological membranes and coupling of ion and water fluxes across epithelia. The discussion of functions is based on a comparative approach analyzing mechanisms that have evolved in different taxonomic groups at biochemical, cellular and tissue levels and their integration in maintaining whole body water and ion homeostasis. The focus is on recent studies of adaptations and newly discovered mechanisms of acclimatization during transitions of animals between different osmotic environments. Special attention is paid to hypotheses about the diversity of cellular organization of osmoregulatory and excretory organs such as glomerular kidneys, antennal glands, Malpighian tubules and insect gut, gills, integument and intestine, with accounts on experimental approaches and methods applied in the studies. It is demonstrated how knowledge in these areas of comparative physiology has expanded considerably during the last two decades, bridging seminal classical works with studies based on new approaches at all levels of anatomical and functional organization. A number of as yet partially unanswered questions are emphasized, some of which are about how water and solute exchange mechanisms at lower levels are integrated for regulating whole body extracellular water volume and ion homeostasis of animals in their natural habitats. © 2014 American Physiological Society.

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Structure and Regulation of the Amiloride-Sensitive Epithelial Sodium Channel

Barbry

Lazdunski

1996

Ion Channels

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Invertebrate epithelial Na+ channels: amiloride-induced current-noise in crab gill

Cited by 44 publications

References 28 publications

How to overcome osmotic stress? Marine crabs conquer freshwater. New insights from modern electrophysiology

How to overcome osmotic stress? Marine crabs conquer freshwater. New insights from modern electrophysiology

Osmoregulation and Excretion

Structure and Regulation of the Amiloride-Sensitive Epithelial Sodium Channel

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