Selective suppression of some components of spontaneous activity in various types of smooth muscle by iproveratril (verapamil)

Golenhofen, K.; Lammel, E.

doi:10.1007/bf00589130

Cited by 150 publications

(66 citation statements)

References 15 publications

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“…In some preparations, mechanical activity was strongly inhibited by cromakalim even when the slow wave amplitude was not reduced or even increased. In gastric antral muscle, the spikelike component at the top of the slow wave is considered the main determinant of the magnitude of the phasic contraction (Golenhofen & Lammel, 1972). Verapamil inhibits the spikelike component with little effect on slow waves and suppresses mechanical activity.…”

Section: Discussionmentioning

confidence: 99%

“…Spontaneous electrical activity, which takes the form of slow waves in the antrum region of the guinea-pig stomach, is known to be relatively insensitive to Ca2" channel blockers, such as verapamil (Golenhofen & Lammel, 1972). The frequency and amplitude of the slow wave are also only very weakly voltage-dependent, when studied by the sucrosegap method (Tomita, 1981).…”

Section: Introductionmentioning

confidence: 99%

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Effects of cromakalim on the electrical slow wave in the circular muscle of guinea‐pig gastric antrum

N¹,

Huang²,

Tomita³

et al. 1993

British J Pharmacology

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1 In circular muscle strips of the antrum of guinea-pig stomach, the effects of cromakalim were studied on mechanical activity and intracellular membrane potential.2 Cromakalim inhibited mechanical activity at concentrations higher than 1 .tM, accompanied by membrane hyperpolarization and a decrease in membrane resistance. The hyperpolarization was markedly potentiated in K+-free solution and was still observed in the absence of Na+. 3 Slow wave electrical activity was relatively resistant to cromakalim. Changes in its amplitude and frequency were not consistent but blockade of slow waves was never observed. In many preparations cromakalim induced spike-like potentials at the top of slow waves, or when spike-like potentials already existed they were potentiated. However, mechanical activity was always inhibited. 4 Inhibition by cromakalim of the phasic contractions associated with the slow waves, could not be reversed by increasing the external K+ concentration (12-30 mM). 5 The results suggest that in guinea-pig stomach muscle mechanical suppression by cromakalim does not simply result from membrane hyperpolarization or from inhibition of slow waves. A clear dissociation was found between the mechanical and electrical activities. Slow waves, particularly their frequency, are relatively insensitive to membrane hyperpolarization.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of cromakalim on the electrical slow wave in the circular muscle of guinea‐pig gastric antrum

N¹,

Huang²,

Tomita³

et al. 1993

British J Pharmacology

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“…Thus, the trigger Ca for Ca release from the intracellular stores can be considered to enter via some Ca binding sites which are sensitive to La (KAWAMURA and YABU, 1978) and much more resistant to verapamil, because K-induced contracture was little inhibited by 10 ,uM verapamil ( Fig. 3B) which is also known as a Ca blocker (GOLENHOFEN and LAMMEL, 1972). It may be also argued that ACh-sensitive Ca store was depleted even after immersion in Ca-free high-K solution (without EGTA) in which no contracture was observed.…”

Section: Discussionmentioning

confidence: 99%

Contribution of intracellular stored calcium to contractile activation in contractures of stomach circular muscle of Bufo vulgaris formosus.

Shinohara¹,

Isao²

1984

Jpn.J.Physiol

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Contractile responses of stomach circular muscle of Bufo to high-K, to acetylcholine (ACh) in normal Ringer or in high-K solution, and to calcium in Ca-free high-K solution showed a phasic contraction which relaxed completely in 30-45 sec. K-induced contracture was abolished in Ca-free solution containing 1 mM ethylene glycol bis(j3-aminoethyl ether)-N,N'-tetraacetic acid (EGTA) within 20 sec, while ACh-induced contracture was not abolished and 10-25 % of control tension was kept up to 40 sec. This response increased to 40-50% when all extracellular Na was replaced with tris(hydroxymethyl)-aminomethane (Tris). K-induced contracture was inhibited completely by 1 mM La. ACh-induced contracture in the muscle depolarized by high-K solution was dependent on the depolarization time, 0-10, b0-70, and nearly 100% of control after 1, 3, and 10 min depolarization, respectively. These ACh-induced contractures were not inhibited by 1 mM EGTA or La. All contractures mentioned above were markedly inhibited by 5 mM procaine. These results suggest that activation of both contractures induced by high-K and ACh were, at least partly, dependent on the Ca at the intracellular Ca storage sites. Ca-induced contracture was dependent on depolarization time as was ACh-induced contracture, when the muscle was depolarized by Ca-free high-K solution without pre-treatment with Ca-free Ringer solution. These results suggest that activation of Ca-contracture is also dependent on intracellular stored Ca.

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“…Furthermore, a new class of Ca 2+ -activated Cl -channel, anoctamin 1 (ANO1)/Tmem16a has been recently identified (Caputo et al, 2008;Yang et al, 2008). The spontaneous activity is not inhibited by a number of 1,4-dihydropyridine Ca 2+ channel antagonists, such as verapamil (Golenhofen et al, 1972), diltiazem (Ishikawa et al, 1985) and nifedipine (Liu et al, 1995;Dickens et al, 1999;Ishikawa et al, 2004). Therefore, unlike smooth muscle cells, ICC-MY pacemaking does not employ L-type Ca 2+ channels as the major Ca 2+ signaling pathway except for the ICC in the submucosal region (ICC-SM) of the murine proximal colon (Yoneda et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Changes in contractile and electrical activity in the ileum of DSS-induced colitis model W/Wv mutant mice

Matsuyoshi

Nakagawa

Zhang

et al. 2010

J. Smooth Muscle Res.

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Selective suppression of some components of spontaneous activity in various types of smooth muscle by iproveratril (verapamil)

Cited by 150 publications

References 15 publications

Effects of cromakalim on the electrical slow wave in the circular muscle of guinea‐pig gastric antrum

Effects of cromakalim on the electrical slow wave in the circular muscle of guinea‐pig gastric antrum

Contribution of intracellular stored calcium to contractile activation in contractures of stomach circular muscle of Bufo vulgaris formosus.

Changes in contractile and electrical activity in the ileum of DSS-induced colitis model W/Wv mutant mice

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