High-affinity binding sites for [3H]saxitoxin are associated with voltage-dependent sodium channels in portal vein smooth muscle

Mironneau, Jean; Martin, Cécile; Arnaudeau, Serge; Jmari, K; Rakotoarisoa, Lala; Sayet, I.; Mironneau, C.

doi:10.1016/0014-2999(90)90624-f

Cited by 22 publications

(18 citation statements)

References 9 publications

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“…There was no change in the slope of the curves (k = 7.2 mV). (Okabe et al, 1988;Ohya & Sperelakis, 1989;Mironneau et al, 1990). In the present experiments the peak amplitude of the Na4 current was observed nearly 1-2ms after application of the command pulse.…”

Section: Discussionmentioning

confidence: 48%

“…However, some reports showed that the dihydropyridine-sensitive, high-threshold Ca2 + channel or L-type channel was predominant in several smooth muscles (Inoue et al, 1989;Honore et al, 1989). More recently, tetrodotoxin-sensitive Na+ currents have been described in dissociated cells from visceral and vascular smooth muscles (Amedee et al, 1986;Okabe et al, 1988;Ohya & Sperelakis, 1989;Mironneau et al, 1990;Martin et al, 1990).…”

Section: Methodsmentioning

confidence: 99%

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Effect of dihydropyridines on calcium channels in isolated smooth muscle cells from rat vena cava

Mironneau

Yamamoto

Sayet

et al. 1992

British J Pharmacology

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1 Whole-cell patch-clamp method was applied to single smooth muscle cells freshly isolated from the rat inferior vena cava.2 Depolarizing pulses, applied from a holding potential of -90mV, activated both Na+ and Ca2+ channels. The fast Na+ current was inhibited by nanomolar concentrations of tetrodotoxin (TTX). The slow Ba2+ current (measured in 5 mM Ba2+ solution) was inhibited by Cd2+ and modulated by dihydropyridine derivatives. When the cells were held at a holding potential of -80 mV, racemic Bay K 8644 increased the Ba2+ current (ED50 = 10nM) while racemic isradipine inhibited the current (IC50 = 21 nM).

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Section: Discussionmentioning

confidence: 48%

Section: Methodsmentioning

confidence: 99%

Effect of dihydropyridines on calcium channels in isolated smooth muscle cells from rat vena cava

Mironneau

Yamamoto

Sayet

et al. 1992

British J Pharmacology

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“…In those tissues that were capable of generating action potentials the charge carrier was thought to be Ca2+ (Nonomura, Hotta & Ohashi, 1966;Brading, Biilbring & Tomita, 1969 Bury & Shuba (1976) found that TTX had no effect on inward current in guinea-pig ureter. However, in recent times with the application of the whole-cell patch-clamp technique, INa has been demonstrated in all three of these tissues (Amedee, Renaud, Jmari, Lombet, Mironneau & Lazdunski, 1986;Ohya & Sperelakis, 1989;Mironneau et al 1990;Muraki, Imaizumi & Watanabe, 1991). This suggests either that the limitations of the sucrose-gap technique were too great to enable demonstration of the current (although the technique was used successfully to demonstrate INa in the heart; Rougier, Vassort & Stiimfli, 1968) or that these tissues are heterogeneous with some cells possessing the current while others do not.…”

Section: Discussionmentioning

confidence: 99%

Tetrodotoxin‐Sensitive Sodium Current in Sheep Lymphatic Smooth Muscle

Hollywood

Cotton

Thornbury

et al. 1997

The Journal of Physiology

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1. Fast inward currents were elicited in freshly isolated sheep lymphatic smooth muscle cells by depolarization from a holding potential of -80 mV using the whole-cell patch-clamp technique. The currents activated at voltages positive to -40 mV and peaked at 0 mV. 2. When sodium chloride in the bathing solution was replaced isosmotically with choline chloride inward currents were abolished at all potentials. 3. These currents were very sensitive to tetrodotoxin (TTX). Peak current was almost abolished at 1 /,M with half-maximal inhibition at 17 nM.4. Examination of the voltage dependence of steady state inactivation showed that more than 90 % of the current was available at the normal resting potential of these cells (-60 mV). 5. The time course of recovery from inactivation was studied using a double-pulse protocol and showed that recovery was complete within 100 ms with a time constant of recovery of 20 ms.6. Under current clamp, action potentials were elicited by depolarizing current pulses. These had a rapid upstroke and a short duration and could be blocked with 1 /LM TTX. 7. Spontaneous contractions of isolated rings of sheep mesenteric lymphatic vessels were abolished or significantly depressed by 1 /uM TTX.

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“…In primary cultured smooth muscle cells isolated from azygos vein of the neonatal rat, a large Na+ current has been observed (Sturek & Hermsmeyer, 1986). Recently, it has been reported that freshly isolated smooth muscle cells from rat myometrium (Ohya & Sperelakis, 1989) and portal vein (Okabe, Kajioka, Nakao, Kitamura & Kuriyama, 1990;Mironneau, Martin, Arnaudeau, Jmari, Rakotoarisoa, Sayet & Mironneau, 1990) also have a fast Na+ current which is highly sensitive to TTX. However, a clear line of evidence for a substantial contribution of a fast Na+ current to the rising phase of action potentials under physiological conditions has not been shown yet in any smooth muscle cells, while the possibility has been suggested in myometrium (Amedee, Renaud, Jmari, Lombet, Mironneau & Lazdunski, 1986).…”

Section: Sodium Currents In Smooth Muscle Cells Freshly Isolated Frommentioning

confidence: 99%

“…Although selectivity of the channel to Na+ was not examined exactly, it appeared to be as high as usual for a TTXsensitive Na+ channel. The existence of INa has been reported in smooth muscle cells from the rabbit pulmonary artery (Okabe et al 1988), the pregnant rat myometrium (Ohya & Sperelakis, 1989) and the rat portal vein (Okabe et al 1990;Mironneau et al 1990). …”

Section: Na+ Current In Smooth Musclementioning

confidence: 99%

Sodium currents in smooth muscle cells freshly isolated from stomach fundus of the rat and ureter of the guinea‐pig.

Muraki

Imaizumi

Watanabe

1991

The Journal of Physiology

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SUMMARY1. Inward currents elicited by depolarization from holding potentials of -80 to -10 mV in single smooth muscle cells isolated from stomach fundus of the rat and ureter of the guinea-pig had two components. The initial fast component (Ifi) was activated and mostly inactivated within 1 2 and 10 ms, respectively, at 21 'C. The following sustained component (ISi) lasted over 50 and 500 ms in fundus and ureter cells, respectively. Iii was blocked by tetrodotoxin but not affected by 05 ,/M-ftconotoxin in both types of cells. 'Si was abolished by the substitution of extracellular Ca2+ with Mn2+.2. The sensitivity of Ifis to TTX was markedly different in fundus and ureter cells. The half-inhibition was obtained at 870 and 11 nm, respectively. The amplitude of Ifi was highly dependent on extracellular Na+ concentration in a solution containing 2-2 mM-Mn2' and 0 mM-Ca21 in both cells. It is concluded that Ifis in these cells are TTX-sensitive and pu-conotoxin-insensitive Na+ currents.3. Some of the kinetics ofINa measured at 10 'C were markedly different in fundus and ureter cells. The current-voltage relationships for Ifi in fundus and ureter cells had peaks at about -10 and 0 mV, respectively. The voltage dependence of the steady-state inactivation ofIfi was also significantly different in these cell types. The half-inactivation voltages were about -74 and -45 mV, respectively. The recovery time course from inactivation in fundus cells was about 10 times slower than that in ureter at -80 mV, where it was 25 ms.4. The contribution of Ifi to the rising phase of an action potential was examined using TTX under current clamp mode at 21 'C. A fast notch-like potential elicited by a subthreshold stimulus for action potential generation was blocked by TTX in both types of cells. Action potentials elicited by a stimulus around threshold were occasionally suppressed by TTX, whereas an action potential was never observed when extracellular Ca2+ was replaced with Mn2+.5. In conclusion, the existence of at least two types of Na+ channel currents, which were distinguished by their TTX sensitivity and kinetics, was strongly suggested in smooth muscle cells from the rat fundus and the guinea-pig ureter

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High-affinity binding sites for [3H]saxitoxin are associated with voltage-dependent sodium channels in portal vein smooth muscle

Cited by 22 publications

References 9 publications

Effect of dihydropyridines on calcium channels in isolated smooth muscle cells from rat vena cava

Effect of dihydropyridines on calcium channels in isolated smooth muscle cells from rat vena cava

Tetrodotoxin‐Sensitive Sodium Current in Sheep Lymphatic Smooth Muscle

Sodium currents in smooth muscle cells freshly isolated from stomach fundus of the rat and ureter of the guinea‐pig.

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