A HIGH‐CONDUCTANCE CALCIUM‐DEPENDENT CHLORIDE CHANNEL IN <i>ASCARIS SUUM</i> MUSCLE

Thorn, Peter; Martin, R. J.

doi:10.1113/expphysiol.1987.sp003053

Cited by 38 publications

(39 citation statements)

References 13 publications

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“…Activity of maxi-Cl Ϫ is, however, blocked by DIDS or SITS (4,5,23). Second, voltage-dependent suppression at high depolarization is observed in hTTYH3 and in some CaC channels (1,24,25). However, the voltage-dependent suppression of the maxi-Cl Ϫ channel is characterized as a "bell-shaped" relation; suppression to the opening is observed in highly depolarized and in deep repolarized potentials (26).…”

Section: Discussionmentioning

confidence: 99%

“…To our knowledge, less than 12 cells possessing maxiCl Ϫ channels have been found over the past 40 years. A maxiCl Ϫ channel in muscle or in other tissues is activated directly by cytosolic Ca 2ϩ (1,2), whereas activity of the channel in other tissues is independent of Ca 2ϩ (3,4). GTP-binding protein (5), cell volume (3), and protein kinases (6) have been reported to modify the function of a maxi-Cl Ϫ channel.…”

Section: Makoto Suzuki ‡ and Atsuko Mizunomentioning

confidence: 99%

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A Novel Human Cl- Channel Family Related to Drosophila flightless Locus

Suzuki

Mizuno

2004

Journal of Biological Chemistry

135

181

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Large conductance chloride (maxi-Cl ؊ ) currents have been recorded in some cells, but there is still little information on the molecular nature of the channel underlying this conductance. We report here that tweety, a gene located in Drosophila flightless, has a structure similar to those of known channels and that human homologues of tweety (hTTYH1-3) are novel maxi-Cl ؊ channels. hTTYH3 mRNA was found to be distributed in excitable tissues. The whole cell current of hTTYH3 was large enough to be discriminated from the control but emerged only after treatment with ionomycin. Analysis of pore mutants suggested that positively charged amino acids contributed to anion selectivity. Like a maxi-Cl ؊ channel in situ, the hTTYH3 single channel showed 26-picosiemen linear current voltage, complex kinetics, 4,4-diisothiocyanato-stilbene-2,2-disulfonic acid sensitivity, subconductance, and the permeability order of I ؊ > Br ؊ > Cl ؊ . Similarly, hTTYH2 encoded an ionomycin-induced maxi-Cl ؊ channel, but TTYH1 encoded a Ca 2؉ -independent and swelling-activated maxiCl ؊ channel. Therefore, the hTTYH family encoded maxi-Cl ؊ channels of mammals. Further studies on the hTTYH family should lead to the elucidation of physiological and pathophysiological roles of novel Cl ؊ channel molecules.

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Section: Discussionmentioning

confidence: 99%

Section: Makoto Suzuki ‡ and Atsuko Mizunomentioning

confidence: 99%

A Novel Human Cl- Channel Family Related to Drosophila flightless Locus

Suzuki

Mizuno

2004

Journal of Biological Chemistry

135

181

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“…The vesicles were transferred to the experimental chamber where recordings were made at room temperature (15-22°C Ca2'-free to avoid contamination of patch recordings with Ca2'-activated ClP channels known to occur in this membrane (Thorn & Martin, 1987). In experiments to determine ion-selectivity of the channel, the ionic composition of the bath solution was altered by diluting 50:50 with distilled H20.…”

Section: Electrical Recordingsmentioning

confidence: 99%

Levamisole‐activated single‐channel currents from muscle of the nematode parasite Ascaris suum

Robertson

Martin

1993

British J Pharmacology

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1 The patch-clamp technique was used to examine levamisole-activated channels in muscle vesicles from Ascaris suum. Cell-attached and isolated inside-out patches were used. At the higher concentration of levamisole (30 JM and 90 gAM) long closed-times separating 'clusters' of bursts were observed, at both hyperpolarized and depolarized membrane potentials and this was interpreted as desensitization.

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“…Two are potassium currents: a non-inactivating potassium current of the Hodgkin-Huxley type and a potassium current of type A (Martin et al 1992). A third source of hyperpolarization is a calcium-activated chloride current (Thorn & Martin, 1987), and in the model it is essential for the termination of the trains of spikes. For this last current, in the absence of experimental data, a triggering level of calcium for the opening of the chloride channel has to be assumed.…”

Section: Methodsmentioning

confidence: 99%

“…The model for a muscle cell described by Turner (1997) was a minimal model with a slow depolarizing current, a hyperpolarizing current, and a leak current, similar to that used by Chay (1990). The present paper presents a model muscle cell based mainly on the extensive work of Martin and collaborators (Thorn & Martin, 1987;Martin et al 1992;Martin & Valkanov, 1996, and references therein), who have elucidated the many ionic currents in the Ascaris muscle cell and described many of the properties of the currents.…”

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confidence: 99%

A Model for an Ascaris Muscle Cell

Turner¹

2001

Experimental Physiology

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Muscle cells in the nematode Ascaris suum undergo bouts of oscillation in the behaving worm, these being correlated with progressing waves of contraction along the body of the worm. The bouts have three time scales: a rough period of 7‐20 s, 10‐20 short bursts of spikes within a bout, and three to eight spikes per burst. This paper has two aims: showing that there is consistency between measurements of individual currents and measurements on whole muscle cells, and creating a building block to eventually explain the locomotion in this ‘simple’ system. A realistic model for a single Ascaris suum muscle cell is developed using existing data from experiments which have established the types of ionic currents in the muscle cell and many of their kinetic properties. Numerical simulations are carried out. The model cell reproduces the two shorter time scales present. It has some robustness with regard to parameter changes, but also allows for the different numbers of spikes per burst seen in recordings from muscle cells. The third time scale, the length of a bout, may originate from some system effect, a combination of neural and stretch effects and possibly a secondary effect of the calcium‐activated chloride channel.

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A HIGH‐CONDUCTANCE CALCIUM‐DEPENDENT CHLORIDE CHANNEL IN ASCARIS SUUM MUSCLE

Abstract: SUMMARYThe properties of a high-conductance Ca-dependent Cl channel in the body muscle membrane of the nematode parasite Ascaris

Cited by 38 publications

References 13 publications

A Novel Human Cl- Channel Family Related to Drosophila flightless Locus

A Novel Human Cl- Channel Family Related to Drosophila flightless Locus

Levamisole‐activated single‐channel currents from muscle of the nematode parasite Ascaris suum

A Model for an Ascaris Muscle Cell

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