Cyclopiazonic Acid is a Specific Inhibitor of the Ca2+-ATPase of Sarcoplasmic Reticulum

Seidler, Norbert W.; Jóna, István; Végh, Marcell Zoltán; Martonosi, Anthony

doi:10.1016/s0021-9258(19)84646-x

“…The IC 50 for eosin is 2-fold higher than for CE (Gatto and Milanick 1993). For the SERCA inhibition experiments, cells were continuously perfused with CPA during the experiment (Seidler et al 1989). The bath solution was changed from normal Ringer's solution (145 mM Na + ) to low (8 mM) Na + for the NCXreversal experiments.…”

Section: Solutionsmentioning

confidence: 99%

Role of Plasma Membrane Calcium ATPases in Calcium Clearance from Olfactory Sensory Neurons

Saidu

¹

,

Weeraratne

²

,

Valentine

³

et al. 2009

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Odorants cause Ca(2+) to rise in olfactory sensory neurons (OSNs) first within the ciliary compartment, then in the dendritic knob, and finally in the cell body. Ca(2+) not only excites but also produces negative feedback on the transduction pathway. To relieve this Ca(2+)-dependent adaptation, Ca(2+) must be cleared from the cilia and dendritic knob by mechanisms that are not well understood. This work focuses on the roles of plasma membrane calcium pumps (PMCAs) through the use of inhibitors and mice missing 1 of the 4 PMCA isoforms (PMCA2). We demonstrate a significant contribution of PMCAs in addition to contributions of the Na(+)/Ca(2+) exchanger and endoplasmic reticulum (ER) calcium pump to the rate of calcium clearance after OSN stimulation. PMCAs in neurons can shape the Ca(2+) signal. We discuss the contributions of the specific PMCA isoforms to the shape of the Ca(2+) transient that controls signaling and adaptation in OSNs.

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“…We previously observed that CPA at 10 μM concentration, which was previously shown to deplete intracellular stores [25], potentiates 5-HT-mediated vascular contractions [15]. In addition, CPA-potentiated responses were partially inhibited by methysergide [15].…”

Section: Effects Of Cpa and Ketanserin On 5-ht-induced Ca 2+ Elevations Following Pkc Inhibitionmentioning

confidence: 82%

The Contribution of Protein Kinase C to Cyclopiazonic Acid-Mediated Potentiation of Serotonin-Induced Vascular Calcium Responses

Selli¹

2017

HJBC

0

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Ö Z Ö nceki çalışmalar 5-HT reseptör antagonisti metiserjidin, siklopiazonik asitin (CPA) potansiyalize ettiği serotonine (5-hidroksitriptamin, 5-HT) bağlı kontraksiyonları kısmen inhibe ettiği gösterilmiş ve azalan antagonistik etkiye protein kinaz C (PKC)-aracılı reseptör internalizasyonunun katkıda bulunduğu önerilmiştir. Bu çalışmada, PKC inhibisyonu varlığında CPA ve 5-HT reseptör antagonistleri metiserjid ve ketanserinin 5-HT'ye bağlı vasküler kalsiyum yanıtları üzerindeki etkileri araştırılmıştır. Bu amaçla A7r5 vasküler düz kas hücrelerindeki hücre içi kalsiyum düzeylerindeki değişimler fluoresan indikatör fura-2 ile spektrofluorometri yöntemi ile belirlenmiştir. Hücreler PKC inhibitörü D-sifingozin ile inkübe edilmiştir. Metodolojik açıdan bakıldığında, aşırı yoğun hücrelerde ajanlara alınan yanıtları gizleyecek düzeyde spontan kalsiyum salınımları belirlenmiştir. 5-HT'ye bağlı kalsiyum yanıtları D-sifingozin ile inkübe edilen hücrelerde kontrol hücrelere göre anlamlı düzeyde azalmıştır. PKC inhibisyonu varlığında CPA, 5-HT'ye bağlı kalsiyum yanıtlarını anlamlı düzeyde potansiyalize etmiştir. Bunun yanı sıra ketanserin, potansiyalize yanıtları kısmen ve anlamlı olmayan düzeyde inhibe etmiştir. Sonuç olarak, hücrelerin aşırı yoğunlukta olması ani kalsiyum tepe (spike) yanıtlarının oluşmasına neden olabilmekte ve hücre içi kalsiyum düzeylerinin izlendiği çalışmalarda hücrelerin optimum yoğunlukta kullanılmasının önemini göstermektedir. Bulgularımız PKC'nin, 5-HT yanıtları üzerindeki CPA-aracılı potansiyalizasyon ve azalmış antagonistik etkiye kısmen aracılık ettiğini göstermiştir. Anahtar KelimelerCPA, D-sifingozin, kalsiyum, serotonin. A B S T R A C TW e previously showed that serotonin (5-Hydroxytryptamine, 5-HT) receptor antagonist methysergide partially inhibited cyclopiazonic acid (CPA)-potentiated and 5-HT-induced contractions suggesting the contribution of protein kinase C (PKC)-mediated receptor internalization in attenuated antagonism. In the present study, the effects of CPA and 5-HT receptor antagonist methysergide and ketanserin on 5-HT-induced calcium responses following PKC inhibition were further investigated. For this purpose, intracellular calcium levels were monitored in A7r5 vascular smooth muscle cells by spectrofluorometry using the fluorescent indicator fura-2. Cells were pre-incubated with specific PKC inhibitor D-sphingosine. In experimental aspects, spontaneous calcium oscillations hindering the monitoring of responses were determined in over confluent cells. 5-HT-induced calcium levels were significantly decreased in D-sphingosine-treated cells compared to control. CPA significantly potentiated 5-HT-induced calcium responses while ketanserin partially but insignificantly inhibited the potentiated responses in the presence of PKC inhibition. In conclusion, increased cell confluency may result in the generation of spontaneous calcium spikes indicating the importance of using optimum cell density for monitoring of intracellular calcium levels. The data suggests that CPA-mediated pote...

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“…CPA pre-treatment also abrogated the effects of caffeine 30 . Yet previous Ca 2+ fluorescence studies performed in rat soleus and oesophageal striated muscle using fluo-3-AM and fura-PE3-AM had reported that both caffeine and CPA increased bulk cytosolic [Ca 2+ ] [31][32][33][34] . However, in contrast to modifying RyR-mediated SR Ca 2+ release, CPA inhibits SR Ca 2+ -ATPase (SERCA)-mediated cytosolic Ca 2+ re-uptake 31,32 .…”

mentioning

confidence: 84%

“…Yet previous Ca 2+ fluorescence studies performed in rat soleus and oesophageal striated muscle using fluo-3-AM and fura-PE3-AM had reported that both caffeine and CPA increased bulk cytosolic [Ca 2+ ] 31 – 34 . However, in contrast to modifying RyR-mediated SR Ca 2+ release, CPA inhibits SR Ca 2+ -ATPase (SERCA)-mediated cytosolic Ca 2+ re-uptake 31 , 32 . The consequent store Ca 2+ depletion would then be expected to reduce, rather than increase, RyR1-mediated Ca 2+ influx into the T-SR junction 30 .…”

Section: Introductionmentioning

confidence: 99%

Finite element analysis predicts Ca2+ microdomains within tubular-sarcoplasmic reticular junctions of amphibian skeletal muscle

Bardsley

¹

,

Matthews

²

,

Huang

³

2021

Sci Rep

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A finite element analysis modelled diffusional generation of steady-state Ca2+ microdomains within skeletal muscle transverse (T)-tubular-sarcoplasmic reticular (SR) junctions, sites of ryanodine receptor (RyR)-mediated SR Ca2+ release. It used established quantifications of sarcomere and T-SR anatomy (radial diameter $$d=220 \, \mathrm{n}\mathrm{m}$$ d = 220 n m ; axial distance $$w=12 \, \mathrm{n}\mathrm{m}$$ w = 12 n m ). Its boundary SR Ca2+ influx densities,$${J}_{\mathrm{influx}}$$ J influx , reflected step impositions of influxes, $$\it {\Phi }_{\mathrm{influx}}={J}_{\mathrm{influx}}\left(\frac{\pi {d}^{2}}{4}\right),$$ Φ influx = J influx π d 2 4 , deduced from previously measured Ca2+ signals following muscle fibre depolarization. Predicted steady-state T-SR junctional edge [Ca2+], [Ca2+]edge, matched reported corresponding experimental cytosolic [Ca2+] elevations given diffusional boundary efflux$$\it \it {\Phi }_{\mathrm{efflux}}=\frac{D [ {{{\mathrm{Ca}}^{2+}}}]_{\mathrm{edge}}}{\lambda } (\pi dw),$$ Φ efflux = D [ Ca 2 + ] edge λ ( π dw ) , established cytosolic Ca2+ diffusion coefficients $$(D = 4 \times {10}^{7} \mathrm{nm}^{2}/\mathrm{s})$$ ( D = 4 × 10 7 nm 2 / s ) and exit length $$\lambda = 9.2 \, \mathrm{n}\mathrm{m}$$ λ = 9.2 n m . Dependences of predicted [Ca2+]edge upon $${J}_{\mathrm{influx}}$$ J influx then matched those of experimental [Ca2+] upon Ca2+ release through their entire test voltage range. The resulting model consistently predicted elevated steady-state T-SR junctional ~ µM-[Ca2+] elevations radially declining from maxima at the T-SR junction centre along the entire axial T-SR distance. These [Ca2+] heterogeneities persisted through 104- and fivefold, variations in D and w around, and fivefold reductions in d below, control values, and through reported resting muscle cytosolic [Ca2+] values, whilst preserving the flux conservation ($$\it \it {\Phi }_{\mathrm{influx}}={\Phi }_{\mathrm{efflux}})$$ Φ influx = Φ efflux ) condition, $${\left[\mathrm{C}{\mathrm{a}}^{2+}\right]}_{\mathrm{edge}}=\frac{\lambda {dJ}_{\mathrm{influx}}}{4Dw}$$ C a 2 + edge = λ dJ influx 4 D w . Skeletal muscle thus potentially forms physiologically significant ~ µM-[Ca2+] T-SR microdomains that could regulate cytosolic and membrane signalling molecules including calmodulin and RyR, These findings directly fulfil recent experimental predictions invoking such Ca2+ microdomains in observed regulatory effects upon Na+ channel function, in a mechanism potentially occurring in similar restricted intracellular spaces in other cell types.

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Cyclopiazonic Acid is a Specific Inhibitor of the Ca2+-ATPase of Sarcoplasmic Reticulum

Cited by 695 publications

References 34 publications

Role of Plasma Membrane Calcium ATPases in Calcium Clearance from Olfactory Sensory Neurons

Role of Plasma Membrane Calcium ATPases in Calcium Clearance from Olfactory Sensory Neurons

The Contribution of Protein Kinase C to Cyclopiazonic Acid-Mediated Potentiation of Serotonin-Induced Vascular Calcium Responses

Finite element analysis predicts Ca2+ microdomains within tubular-sarcoplasmic reticular junctions of amphibian skeletal muscle

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