Ca2+ release-activated channels in rat stomach smooth muscle cells

Smaili, Soraya Soubhi; Cavalcanti, P. M. S.; Oshiro, Maria E.M.; Ferreira, Alice Teixeira; Jurkiewicz, Aron

doi:10.1016/s0014-2999(97)01537-9

Cited by 16 publications

(7 citation statements)

References 12 publications

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“…Recently, a phenomenon called capacitative Ca 2ϩ entry, which is regulated by Ca 2ϩ concentration in intracellular stores, was observed in some nonexcitable cells and smooth muscle tissues [9,11,25,26]. SK&F 96365 is among the most widely used inhibitors of capacitative Ca 2ϩ entry [27]. SK&F 96365 antagonized the CPA-induced increase in the amplitude of RSCs, but it did not antagonize the increase in the frequency.…”

Section: Discussionmentioning

confidence: 99%

Rhythmic Spontaneous Contractions in the Rat Proximal Colon.

Yoneda

Kadowaki²,

Sugimori³

et al. 2001

JJP

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Pulsating contraction waves started from "the turning portion of the colon" in the rat and the guinea pig and propagated both orally as antiperistalsis and anally as peristalsis [1]. Hukuhara and Neya [1] named this portion the "pacemaker area." C-kit immunoreactive cells are known to be interstitial cells of Cajal (ICCs) and to generate pacemaker activity of the gastrointestinal tract [2,3]. Recently in the colonic "pacemaker area" [1] and in the proximal colon in guinea pig, a larger number of special smooth muscle cells corresponding to c-kit immunoreactive cells were found than in the distal colon [4]. We learned that tetrodotoxin (TTX)-insensitive rhythmic spontaneous contractions (RSCs) are present in the rat proximal colon and hypothesized that RSCs are generated and/or regulated by ICCs. To prove our hypothesis, we investigated whether these RSCs are absent in homozygous Ws/Ws mutant rats.A Ws/ϩ mutant rat with white spots and coat color dilution was first found in the inbred colony of the BN/fMai strain [5]. Because homozygous Ws/Ws rats were not obtained in the genetic background of BN/fMai strain, spotted BN/fMai-Ws/ϩ rats were crossed with ϩ/ϩ rats of the Donryu strain. Rats of -ATPase by cyclopiazonic acid (CPA) (10 Ϫ6 M) or by thapsigargin (10 Ϫ6 M) increased the frequency of RSCs. The increasing effects of CPA on the frequency of RSCs were more prominent in Ws/Ws mutant rats than in ϩ/ϩ rats. We concluded that the functional coordination between c-kit negative ICC SM and other mutationally impaired c-kit positive ICC MY and ICC SM may be required for moderate regulation in the frequency of spontaneous activity.

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Section: Discussionmentioning

confidence: 99%

Rhythmic Spontaneous Contractions in the Rat Proximal Colon.

Yoneda

Kadowaki²,

Sugimori³

et al. 2001

JJP

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“…These findings could not be accounted for by the involvement of the single type of Ca 2+ channel in the LTC 4 ‐induced Ca 2+ influx. Recently, the capacitative Ca 2+ influx pathway has been shown to play an important role in the agonist‐induced increase in [Ca 2+ ] i ( Berridge, 1995 ; Smaili et al ., 1998 ). However, this mechanism may not be activated during the stimulation with LTC 4 , because LTC 4 does not induce Ca 2+ store depletion.…”

Section: Discussionmentioning

confidence: 99%

The mechanism for the contraction induced by leukotriene C4 in guinea‐pig taenia coli

Ieiri

Nishimura

Hirano

et al. 2001

British J Pharmacology

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1 The mechanism underlying the LTC 4 -induced contraction of guinea-pig taenia coli was determined using the simultaneous measurements of [Ca 2+ ] i and force in whole muscle preparations. Additional experiments were performed in receptor coupled permeabilized preparation. For comparison purposes, the contraction which was induced by a typical G-protein mediated agonist, carbachol was also characterized. 2 LTC 4 induced a contraction in the guinea-pig taenia coli in a concentration-dependent manner. The maximal response was obtained at 100 nM and the EC 50 value was 5.4+1.9 nM. [Ca 2+ ] i by these drugs was also similar. 6 We thus conclude that LTC 4 induces the contraction of the guinea-pig taenia coli mainly through Ca 2+ in¯ux via both the diltiazem-sensitive and SK&F 96365-sensitive Ca 2+ channels, without a ecting either the Ca 2+ -sensitivity or the intracellular Ca 2+ release. These results indicated that the mechanism underlying the LTC 4 -induced contraction di ers greatly from that for conventional Gprotein mediated agonists, such as carbachol.

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“…Figure 4c shows that addition of Tap induces an increase in Ca 2 þ , such as those promoted by the inhibition of ER Ca 2 þ uptake, 27 and that Bax still induces a Ca 2 þ increase after this treatment. However, this effect was lower than the effect observed in Figure 4a, indicating that Bax may also act on Tap-sensitive stores.…”

Section: Bax Releases Ca M 2 þmentioning

confidence: 98%

Bax affects intracellular Ca2+ stores and induces Ca2+ wave propagation

et al. 2004

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In the present study, we evaluated proapoptotic protein Bax on mitochondria and Ca 2 þ homeostasis in primary cultured astrocytes. We found that recombinant Bax (rBax, 10 and 100 ng/ml) induces a loss in mitochondrial membrane potential (DW m ). This effect might be related to the inhibition of respiratory rates and a partial release of cytochrome c, which may change mitochondrial morphology. The loss of DW m and a selective permeabilization of mitochondrial membranes contribute to the release of Ca 2 þ from the mitochondria. This was inhibited by cyclosporin A (5 lM) and Ruthenium Red (1 lg/ml), indicating the involvement of mitochondrial Ca 2 þ transport mechanisms. Bax-induced mitochondrial Ca 2 þ release evokes Ca 2 þ waves and wave propagation between cells. Our results show that Bax induces mitochondrial alteration that affects Ca 2 þ homeostasis and signaling. These changes show that Ca 2 þ signals might be correlated with the proapoptotic activities of Bax.

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Ca2+ release-activated channels in rat stomach smooth muscle cells

Cited by 16 publications

References 12 publications

Rhythmic Spontaneous Contractions in the Rat Proximal Colon.

Rhythmic Spontaneous Contractions in the Rat Proximal Colon.

The mechanism for the contraction induced by leukotriene C4 in guinea‐pig taenia coli

Bax affects intracellular Ca2+ stores and induces Ca2+ wave propagation

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