The Effects of 2-Aminoethoxydiphenyl Borate, a Novel Inositol 1,4,5-Trisphosphate Receptor Modulator on Myometrial Contractions

doi:10.1006/bbrc.1999.1602

Biochemical and Biophysical Research Communications

Volume 264, Issue 3, 2 November 1999, Pages 979-982

https://doi.org/10.1006/bbrc.1999.1602 Get rights and content

Abstract

These studies were performed to evaluate the effect of 2-aminoethoxydiphenyl borate (2-APB), a novel membrane-permeable inositol 1,4,5-trisphosphate-receptor inhibitor on agonist-induced, spontaneous, and KCl-stimulated in vitro myometrial contractions. 2-APB significantly inhibited spontaneous myometrial contractions as well as phasic contractions induced by various uterotonic agonists. Confiriming its effects on intracellular calcium release, 2-APB inhibited phasic contractions in the absence of extracellular calcium. 2-APB had little effect on the tonic response to KCl stimulation, implicating its insignificant effect on voltage-gated calcium channels. The inhibitory effect of 2-APB on phasic contractions was completely reversed by washout. In summary, 2-APB effectively penetrated uterine tissue and significantly inhibited myometrial events previously shown to be mediated through activation of the PI-signaling pathway.

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Cited by (67)

Novel effect of 2-aminoethoxydiphenylborate through inhibition of calcium sensitization induced by Rho kinase activation in human detrusor smooth muscle
2013, European Journal of Pharmacology
Citation Excerpt :
Since 2-APB was first introduced as an IP3 receptor antagonist permeable across the plasma membrane (Maruyama et al., 1997), subsequent studies carried out in different cells and tissues have revealed that while 2-APB possesses multiple inhibitory actions, these activities are largely limited to ionic channels, such as store-operated Ca2+ channels (Bootman et al., 2002), volume-regulated anion channels (Lemonnier et al., 2004), TRP channels (Hu et al., 2004; Ratz and Berg, 2006), and connexin-based gap junction channels (Harks et al., 2003). In smooth muscle, there are lines of evidence consistent with the first report that 2-APB modulates cellular functions by inhibiting IP3 receptors (Maruyama et al., 1997; Ascher-Landsberg et al., 1999; Imaeda et al., 2000; Hirst and Edwards, 2001; Sergeant et al., 2001), however, unexpected responses have been occasionally observed. Durlu-Kandilci and Brading (2006) have shown that 2-APB attenuates carbachol-induced contraction in β-escin-permeabilized detrusor strips of rat, but this effect is irreproducible in guinea-pig detrusor and intestinal smooth muscle.
Since the introduction of 2-aminoethoxydiphenylborate (2-APB) as a membrane permeable modulator of inositol (1,4,5)-trisphosphate receptors, subsequent studies have revealed additional actions of this chemical on multiple Ca²⁺-permeable ionic channels in the plasma membrane. However, no reports have yet examined 2-APB as a modulator targeting contractile machinery in smooth muscle, independent of Ca²⁺ mobilization, namely Ca²⁺ sensitization. Here, we assessed whether or not 2-APB affects intracellular signaling pathways of Ca²⁺ sensitization for contraction using α-toxin permeabilized human detrusor smooth muscle. Although contractions were induced by application of Ca²⁺-containing bath solutions, 2-APB had little effect on contractions induced by 1 µM Ca²⁺ alone but significantly reversed the carbachol-induced augmentation of Ca²⁺-induced contraction in the presence of guanosine triphosphate (carbachol-induced Ca²⁺ sensitization). The rho kinase inhibitor Y-27632 and protein kinase C inhibitor GF-109203X also reversed the carbachol-mediated Ca²⁺ sensitization. Additional application of 2-APB caused a small but significant further attenuation of the contraction in the presence of GF-109203X but not in the presence of Y-27632. Like carbachol, the rho kinase activator; sphingosylphosphorylcholine, protein kinase C activator; phorbol 12,13 dibutyrate, and myosin light chain phosphatase inhibitor; calyculin-A all induced Ca²⁺ sensitization. However, the inhibitory activity of 2-APB was limited with sphingosylphosphorylcholine-induced Ca²⁺ sensitization. This study revealed a novel inhibitory effect of 2-APB on smooth muscle contractility through inhibition of the rho kinase pathway.
The involvement of calcium carriers and of the vacuole in the glucose-induced calcium signaling and activation of the plasma membrane H<sup>+</sup>-ATPase in Saccharomyces cerevisiae cells
2012, Cell Calcium
Citation Excerpt :
By contrast, they are significantly reduced in both yvc1Δ single and arg82Δ yvc1Δ double mutants. On the other hand, the pre-incubation of yeast cells with 2-APB, an IP3 receptor inhibitor in mammalian cells [38], shows that this drug has an evident inhibitory effect on both glucose-induced calcium signaling and plasma membrane H+-ATPase activation. However, others works also have demonstrated that 2-APB could have other targets, including store-operated Ca2+ channels (SOCs) making its utilization to study IP3-dependent calcium signaling from internal stores a matter of controversy [50,51].
Previous work from our laboratories demonstrated that the sugar-induced activation of plasma membrane H⁺-ATPase in Saccharomyces cerevisiae is dependent on calcium metabolism with the contribution of calcium influx from external medium. Our results demonstrate that a glucose-induced calcium (GIC) transporter, a new and still unidentified calcium carrier, sensitive to nifedipine and gadolinium and activated by glucose addition, seems to be partially involved in the glucose-induced activation of the plasma membrane H⁺-ATPase. On the other hand, the importance of calcium carriers that can release calcium from internal stores was analyzed in glucose-induced calcium signaling and activation of plasma membrane H⁺-ATPase, in experimental conditions presenting very low external calcium concentrations. Therefore the aim was also to investigate how the vacuole, through the participation of both Ca²⁺-ATPase Pmc1 and the TRP homologue calcium channel Yvc1 (respectively, encoded by the genes PMC1 and YVC1) contributes to control the intracellular calcium availability and the plasma membrane H⁺-ATPase activation in response to glucose. In strains presenting a single deletion in YVC1 gene or a double deletion in YVC1 and PMC1 genes, both glucose-induced calcium signaling and activation of the H⁺-ATPase are nearly abolished. These results suggest that Yvc1 calcium channel is an important component of this signal transduction pathway activated in response to glucose addition. We also found that by a still undefined mechanism Yvc1 activation seems to correlate with the changes in the intracellular level of IP₃. Taken together, these data demonstrate that glucose addition to yeast cells exposed to low external calcium concentrations affects calcium uptake and the activity of the vacuolar calcium channel Yvc1, contributing to the occurrence of calcium signaling connected to plasma membrane H⁺-ATPase activation.
Ion channels in the regulation of platelet migration
2011, Biochemical and Biophysical Research Communications
Citation Excerpt :
The present study explored the impact of ion channels on SDF-1 induced platelet migration. To this end platelet migration towards the inflammatory chemokine SDF-1 was determined in the presence and absence of the Orai1 inhibitors 2-aminoethoxydiphenyl borate (2-APB) [33–35] and SKF-96365 [36,37], the unspecific K+ channel inhibitor tetraethylammonium (TEA) [38], the KCa3.1/SK4 specific K+ channel inhibitor clotrimazole [39], as well as the unspecific Cl− channel inhibitor 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) [40–43]. The specific role of KCa3.1/SK4 in platelet migration was further analysed in murine platelets isolated from gene-targeted mice lacking functional SK4 (sk4−/−) and the corresponding wild type littermate mice (sk4+/+).
Platelets have been shown to migrate and thus to invade the vascular wall. Platelet migration is stimulated by SDF-1. In other cell types, migration is dependent on Ca²⁺ entry via Ca²⁺ channels. Ca²⁺ influx is sensitive to cell membrane potential which is maintained by K⁺ channel activity and/or Cl⁻ channel activity. The present study explored the role of ion channels in the regulation of SDF-1 induced migration. Platelets were isolated from human volunteers as well as from gene targeted mice lacking the Ca²⁺ activated K⁺ channel SK4 (sk4^−/−) and their wild type littermates (sk4^+/+). According to confocal microscopy human platelets expressed the Ca²⁺ channel Orai1 and the Ca²⁺-activated K⁺ channel K_Ca3.1 (SK4). SDF-1 (100 ng/ml) stimulated migration in human platelets, an effect blunted by Orai1 inhibitors 2-aminoethoxydiphenyl borate 2-APB (10 μM) and SKF-96365 (10 μM), by unspecific K⁺ channel inhibitor TEA (30 mM), by SK4 specific K⁺ channel blocker clotrimazole (10 μM), but not by Cl⁻ channel inhibitor 5-nitro-2-(3-phenylpropylamino) benzoic acid NPPB (100 μM). Significant stimulation of migration by SDF-1 was further observed in sk4^+/+ platelets but was virtually absent in sk4^−/− platelets. In conclusion, platelet migration requires activity of the Ca²⁺ channel Orai1 and of the Ca²⁺ activated K⁺ channel SK4, but not of NPPB-sensitive Cl⁻ channels.
Alteration of arterial smooth muscle potassium channel composition and BK<inf>Ca</inf> current modulation in hypertension
2005, European Journal of Pharmacology
We investigated K⁺ currents and their regulation by the sarcoplasmic reticulum in mesenteric arterial smooth muscle cells of the spontaneously hypertensive rat (SHR). Using perforated patch-clamp technique, we found the overall K⁺ current density was significantly lower in adult SHR compared to adult Wistar–Kyoto rats (WKY). The K⁺ currents were almost exclusively of large-conductance Ca²⁺-dependent (BK_Ca) variety in SHR, but largely of voltage-gated (Kv) variety in WKY. Western blot assay showed parallel findings. These differences were not observed in pre-hypertensive rats. Depleting the intracellular Ca²⁺ store inhibited the K⁺ currents in adult SHR. Ryanodine augmented the K⁺ current at 1 μM, but suppressed it at 10 μM; 2-aminoethoxydiphenyl borate demonstrated concentration-dependent inhibition. We conclude that an alteration of membrane K⁺ channel composition has resulted in lower overall K⁺ current density. The changes in K⁺ current type may indicate an underlying defect in Ca²⁺-handling that predisposes smooth muscle cells to the hypertensive phenotype.
Involvement of phospholipase C in Yersinia enterocolitica heat stable enterotoxin (Y-STa) mediated rise in intracellular calcium level in rat intestinal epithelial cells
2005, Toxicon
In response to Yersinia enterocolitica heat stable enterotoxin (Y-STa) intracellular calcium level was increased with a prolong sustained phase in presence of calcium chloride in extracellular environment in rat intestinal epithelial cells. Chelation of extracellular calcium with EGTA (extracellular calcium chelator) and suspension of cells in calcium free buffer demonstrated a rapid but transient rise in calcium level, which suggested that Y-STa induced rise in intracellular calcium concentration was the combination of both intracellular calcium store depletion and calcium influx from extracellular environment. Moreover, in response to Y-STa phosphoinositide specific phospholipase C activity and inositol tri phosphate (IP₃) level was increased and U73122, a phospholipase C inhibitor could completely inhibit Y-STa induced calcium rise. However, treatment of rat enterocytes with dantrolene IP₃, a mediated calcium release inhibitor from intracellular store resulted partial inhibition of Y-STa induced rise in intracellular calcium level. Similar observation was noted with IP₃ receptor antagonist 2ABP (2-amino-ethoxydiphenylborate). These results suggested that beside phospholipase C IP₃ pathway, phospholipase C might have an independent role in Y-STa induced calcium influx. Rise in phospholipase Cγ isoform activity in response to Y-STa suggested that γ isoform of phospholipase C might have a role in Y-STa mediated rise in intracellular calcium level.
Activation of osteoblastic functions by a mediator of pain, bradykinin
2004, Biochemical Pharmacology
Citation Excerpt :
Furthermore, we demonstrated that BK increased [Ca2+]i and that HOE140 or 2-APB reduced the BK-increased [Ca2+]i, IL-6, and PGE2 production (Figs. 5 and 6). Since 2-APB is generally used as an IP3R blocker at the dose of 5–100 μM [44–46], these data suggest that BK induced IL-6 and PGE2 synthesis via an IP3-induced increase in intracellular calcium in SaM-1 cells. PGE2 is well known to induce IL-6 production in mouse osteoblastic cells [25].
We investigated the effects of bradykinin (BK) on the production of interleukin (IL)-6 and prostaglandin PGE₂, whose molecules are capable of stimulating the development of osteoclasts from their hematopoietic precursors as well as the signal transduction systems involved, in human osteoblasts (SaM-1 cells). BK receptors B1 (B1R) and B2 (B2R) were expressed in SaM-1 and osteosarcoma (SaOS-2, HOS, and MG-63) cells. Treatment of SaM-1 cells with BK increased the synthesis of both IL-6 and PGE₂ and the increase in both was blocked by HOE140 (B2R antagonist), but not by Des-Arg⁹-[Leu⁸]-BK (B1R antagonist). U-73122, a phospholipase C (PLC) inhibitor, suppressed BK-induced IL-6 and PGE₂ synthesis in SaM-1 cells. In addition, BK caused an increase in the intracellular Ca²⁺ concentration ([Ca²⁺]i), which was inhibited by pretreatment with HOE140 or 2-aminoethoxydiphenyl borate (2-APB), an inositol 1,4,5-trisphosphate (IP₃) receptor (IP₃R) blocker. Furthermore, both SB203580 (an inhibitor of p38 mitogen-activated protein kinase [MAPK]) and PD98059 (an inhibitor of MEK, upstream of ERK) attenuated the BK-induced IL-6 and PGE₂ synthesis. BK treatment resulted in the phosphorylation of p38 MAPK and extracellular signal-regulated kinase (ERK)1/2, and 2-APB could suppress BK-induced phosphorylation of ERK1/2. These findings suggest that BK increased both IL-6 and PGE₂ synthesis in osteoblastic cells via B2R and that PLC, IP₃-induced [Ca²⁺]i, MEK, and MAPKs were involved in the signal transduction in these cells.

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Regular ArticleThe Effects of 2-Aminoethoxydiphenyl Borate, a Novel Inositol 1,4,5-Trisphosphate Receptor Modulator on Myometrial Contractions

Abstract

Cell Signal

Mol. Pharmacol.

J. Biol. Chem.

Science

J. Biochem.

J. Soc. Gynecol. Invest.

Am. J. Obstet. Gynecol.

Regular Article
The Effects of 2-Aminoethoxydiphenyl Borate, a Novel Inositol 1,4,5-Trisphosphate Receptor Modulator on Myometrial Contractions