Mechanotransducing ion channels in C6 glioma cells

Bowman, Charles L.; Lohr, James W.

doi:10.1002/(sici)1098-1136(199611)18:3<161::aid-glia1>3.0.co;2-2

Cited by 21 publications

(9 citation statements)

References 34 publications

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“…The open probability (P o ) was time and voltage dependent, displaying a fast adaptation (within 100 ms at hyperpolarized potentials) similar to that reported for Xenopus oocytes (Hamill and McBride, 1992). The time dependence of P o can be described by an initial phasic period followed by a tonic period, as defined in Bowman and Lohr (1996). Both the duration of the phasic period and P o during the tonic period showed a steep voltage dependence, decreasing as the potential became more negative (Fig.…”

Section: Sac Properties In Activated Adult Rat Astrocytes: Cell-attached Versus Outside-outsupporting

confidence: 73%

“…However, first it was necessary to show that SAC function is maintained in the outside-out patch configuration. To date, all studies investigating the properties and function of SACs in astrocytes have focused on neonatal preparations and C6 glioma cell lines (Bowman et al, 1992;Bowman and Lohr, 1996;Islas et al, 1993) due to difficulties in culturing adult astrocytes. Langan et al (1995) showed that adult-activated rat astrocytes from gel foam implants could be isolated and cultured through Ͼ10 passages, while maintaining all type 1 astrocytic markers [glial fibrillary acidic protein (GFAP), vimentin, 7B11, and RAN2], contact inhibition, and cell cycle kinetics.…”

Section: Sac Properties In Activated Adult Rat Astrocytes: Cell-attached Versus Outside-outmentioning

confidence: 99%

“…In addition, K ϩ -selective SACs and a curvaturesensitive nonselective cation channel have been described in neonatal astrocyte cultures (Bowman et al, 1992;Islas et al, 1993). A cation-selective SAC has also been identified in C6 glioma cells (Bowman and Lohr, 1996). However, none of these channels have been investigated for involvement in RVD.…”

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confidence: 99%

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Identification of a Peptide Toxin fromGrammostola spatulataSpider Venom That Blocks Cation-Selective Stretch-Activated Channels

Suchyna

Johnson

Hamer

et al. 2000

The Journal of General Physiology

327

281

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We have identified a 35 amino acid peptide toxin of the inhibitor cysteine knot family that blocks cationic stretch-activated ion channels. The toxin, denoted GsMTx-4, was isolated from the venom of the spider Grammostola spatulata and has <50% homology to other neuroactive peptides. It was isolated by fractionating whole venom using reverse phase HPLC, and then assaying fractions on stretch-activated channels (SACs) in outside-out patches from adult rat astrocytes. Although the channel gating kinetics were different between cell-attached and outside-out patches, the properties associated with the channel pore, such as selectivity for alkali cations, conductance (∼45 pS at −100 mV) and a mild rectification were unaffected by outside-out formation. GsMTx-4 produced a complete block of SACs in outside-out patches and appeared specific since it had no effect on whole-cell voltage-sensitive currents. The equilibrium dissociation constant of ∼630 nM was calculated from the ratio of association and dissociation rate constants. In hypotonically swollen astrocytes, GsMTx-4 produces ∼40% reduction in swelling-activated whole-cell current. Similarly, in isolated ventricular cells from a rabbit dilated cardiomyopathy model, GsMTx-4 produced a near complete block of the volume-sensitive cation-selective current, but did not affect the anion current. In the myopathic heart cells, where the swell-induced current is tonically active, GsMTx-4 also reduced the cell size. This is the first report of a peptide toxin that specifically blocks stretch-activated currents. The toxin affect on swelling-activated whole-cell currents implicates SACs in volume regulation.

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Section: Sac Properties In Activated Adult Rat Astrocytes: Cell-attached Versus Outside-outsupporting

confidence: 73%

Section: Sac Properties In Activated Adult Rat Astrocytes: Cell-attached Versus Outside-outmentioning

confidence: 99%

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Identification of a Peptide Toxin fromGrammostola spatulataSpider Venom That Blocks Cation-Selective Stretch-Activated Channels

Suchyna

Johnson

Hamer

et al. 2000

The Journal of General Physiology

327

281

View full text Add to dashboard Cite

show abstract

“…On the other hand, an important aspect of MHT process is the SPION internalization for the cells into tumoral tissue, the surface charge (zeta potential) of SPION has influence in the pathways of SPION internalization by tumoral cells [67] due to the negative character of the lipidic bilayer found in the cell membrane external surface [76]. The positive character of SPION surface contributes favorably for their internalization process due to electrostatic action, as seen in C6 cells [77][78][79][80]. In our study, the SPIONa zeta potential displayed positive character (+20 mV) which favored the nanoparticle internalization into C6 tumoral cells as observed in our results.…”

Section: Discussionmentioning

confidence: 46%

Therapeutic Efficiency of Multiple Applications of Magnetic Hyperthermia Technique in Glioblastoma Using Aminosilane Coated Iron Oxide Nanoparticles: In Vitro and In Vivo Study

Rego

Nucci

Mamani

et al. 2020

IJMS

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Magnetic hyperthermia (MHT) has been shown as a promising alternative therapy for glioblastoma (GBM) treatment. This study consists of three parts: The first part evaluates the heating potential of aminosilane-coated superparamagnetic iron oxide nanoparticles (SPIONa). The second and third parts comprise the evaluation of MHT multiple applications in GBM model, either in vitro or in vivo. The obtained heating curves of SPIONa (100 nm, +20 mV) and their specific absorption rates (SAR) stablished the best therapeutic conditions for frequencies (309 kHz and 557 kHz) and magnetic field (300 Gauss), which were stablished based on three in vitro MHT application in C6 GBM cell line. The bioluminescence (BLI) signal decayed in all applications and parameters tested and 309 kHz with 300 Gauss have shown to provide the best therapeutic effect. These parameters were also established for three MHT applications in vivo, in which the decay of BLI signal correlates with reduced tumor and also with decreased tumor glucose uptake assessed by positron emission tomography (PET) images. The behavior assessment showed a slight improvement after each MHT therapy, but after three applications the motor function displayed a relevant and progressive improvement until the latest evaluation. Thus, MHT multiple applications allowed an almost total regression of the GBM tumor in vivo. However, futher evaluations after the therapy acute phase are necessary to follow the evolution or tumor total regression. BLI, positron emission tomography (PET), and spontaneous locomotion evaluation techniques were effective in longitudinally monitoring the therapeutic effects of the MHT technique.

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“…2C of their paper). Bowman and Lohr [1] used a modified syringe to generate negative pressure transmitted to the patch pipette when a single valve was opened. The 10% to 90% response time of their pressure jump was ≅30 ms. Silberberg and Magleby [11] used a computer-activated three-way valve to make pressure steps (from atmospheric), but did not make high time resolution measurements.…”

Section: Comparison With Other Systemsmentioning

confidence: 99%

Application of pressure steps to mechanosensitive channels in membrane patches: a simple, economical, and fast system

Hurwitz

Segal²

2001

Pflügers Arch - Eur J Physiol

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Mechanosensitive channels (MSCs) have been described in a wide variety of cells, but the molecular mechanisms that couple membrane tension or deformation to channel activity (i.e., mechanotransduction) are not understood. The ability to measure the dynamics of the temporal relationship between the pressure stimulus and the channel response is a key tool for gaining insight into mechanotransduction. Several laboratories have designed pressure clamps, but these instruments are complex, costly, and not commercially available. This paper describes a simple and inexpensive system for applying fast pressure steps to a membrane patch. This system is easy to build and achieves submillisecond 20% to 80% step response times on par with the fastest pressure clamp described. Application to a stretch-activated non-selective cation channel in the kidney is used to demonstrate the system.

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Mechanotransducing ion channels in C6 glioma cells

Cited by 21 publications

References 34 publications

Identification of a Peptide Toxin fromGrammostola spatulataSpider Venom That Blocks Cation-Selective Stretch-Activated Channels

Identification of a Peptide Toxin fromGrammostola spatulataSpider Venom That Blocks Cation-Selective Stretch-Activated Channels

Therapeutic Efficiency of Multiple Applications of Magnetic Hyperthermia Technique in Glioblastoma Using Aminosilane Coated Iron Oxide Nanoparticles: In Vitro and In Vivo Study

Application of pressure steps to mechanosensitive channels in membrane patches: a simple, economical, and fast system

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