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

Hurwitz, Craig G.; Segal, Aaron

doi:10.1007/s004240100541

Cited by 8 publications

(3 citation statements)

References 13 publications

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“…For the application of pressure ramps, a syringe pump (YA-12, Yale Apparatus, Wantagh, NY) under negative feedback control (based on the output voltage from the pressure transducer) was connected to the pressure port. For the application of pressure steps, a multivalve pressure system of our own design (14) was connected to the pipette holder. With this system, up to seven different pressure steps (in addition to atmospheric pressure) can be made, typically with a 20-80% step response time of Ͻ1 ms. Pressure step protocols were triggered by PULSE and achieved using a parallel port interface (LPTek, Westbury, NY) controlled by a Visual BASIC program written in our laboratory.…”

Section: Methodsmentioning

confidence: 99%

A mechanogated nonselective cation channel in proximal tubule that is ATP sensitive

Hurwitz¹,

Hu²,

Segal

2002

American Journal of Physiology-Renal Physiology

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Ion channels that are gated in response to membrane deformation or “stretch” are empirically designated stretch-activated channels. Here we describe a stretch-activated nonselective cation channel in the basolateral membrane (BLM) of the proximal tubule (PT) that is nucleotide sensitive. Single channels were studied in cell-intact and cell-free patches from the BLM of PT cells that maintain their epithelial polarity. The limiting inward Cs+ conductance is ∼28 pS, and channel activity persists after excision into a Ca2+- and ATP-free bath. The stretch-dose response is sigmoidal, with half-maximal activation of about −19 mmHg at −40 mV, and the channel is activated by depolarization. The inward conductance sequence is: NH[Formula: see text] ∼ Cs+ ∼ Rb+> K+ ∼ Na+ ∼ Li+ > Ca2+ ∼ Ba2+> N-methyl-d-glucamine ∼ tetraethylammonium. The venom of the common Chilean tarantula, Grammostola spatulata, completely blocks channel activity in cell-attached patches. Hypotonic swelling reversibly activates the channel. Intracellular ATP concentration ([ATP]i) reversibly blocks the channel (inhibitory constant ∼0.48 mM), suggesting that channel function is coupled to the metabolic state of the cell. We conclude that this channel may function as a Ca2+ entry pathway and/or be involved in regulation of cell volume. We speculate this channel may be important when [ATP]i is depleted, as occurs during periods of increased transepithelial transport or with ischemic injury.

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Section: Methodsmentioning

confidence: 99%

A mechanogated nonselective cation channel in proximal tubule that is ATP sensitive

Hurwitz¹,

Hu²,

Segal

2002

American Journal of Physiology-Renal Physiology

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“…Only excised and cell attached patches allow application of a large range of pressures and therefore, the highlighting of the relationship between open probability and membrane tension of a single channel. The development of the pressure clamp system in the nineties ( McBride and Hamill, 1992 ; Hurwitz and Segal, 2001 ) has become a key tool for applying fast pressure steps to membrane patches ( Figure 2B ). The ability to measure channel relaxations following step changes in positive/negative pressure in combination with patch clamp techniques has launched many studies on the analysis of the time, voltage and pressure dependence of the opening and closing of MS channels from different organisms, exemplified in Figure 2B with the Arabidopsis mechanosensitve MSL10 channel.…”

Section: Accessing Ms Activity At Cellular Levelmentioning

confidence: 99%

Mechanosensitive channels: feeling tension in a world under pressure

et al. 2014

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Plants, like other organisms, are facing multiple mechanical constraints generated both in their tissues and by the surrounding environments. They need to sense and adapt to these forces throughout their lifetimes. To do so, different mechanisms devoted to force transduction have emerged. Here we focus on fascinating proteins: the mechanosensitive (MS) channels. Mechanosensing in plants has been described for centuries but the molecular identification of MS channels occurred only recently. This review is aimed at plant biologists and plant biomechanists who want to be introduced to MS channel identity, how they work and what they might do in planta? In this review, electrophysiological properties, regulations, and functions of well-characterized MS channels belonging to bacteria and animals are compared with those of plants. Common and specific properties are discussed. We deduce which tools and concepts from animal and bacterial fields could be helpful for improving our understanding of plant mechanotransduction. MS channels embedded in their plasma membrane are sandwiched between the cell wall and the cytoskeleton. The consequences of this peculiar situation are analyzed and discussed. We also stress how important it is to probe mechanical forces at cellular and subcellular levels in planta in order to reveal the intimate relationship linking the membrane with MS channel activity. Finally we will propose new tracks to help to reveal their physiological functions at tissue and plant levels.

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“…Analysis was carried out using both pClamp software (Axon Instruments, Foster City, CA, USA) and software developed for the purpose in Visual Basic. The stretch activation of channels was induced by applying rapid negative pressure stimuli to the membrane patches, using a two-electrovalve system, similar to that described by Hurwitz and Segal [15].…”

Section: Electrophysiologymentioning

confidence: 99%

Effects of intracellular pH and Ca2+ on the activity of stretch-sensitive cation channels in leech neurons

Barsanti

Pellegrini

Ricci

et al. 2006

Pflugers Arch - Eur J Physiol

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The effects of intracellular pH and calcium on the activity of the leech mechanosensitive cation channels have been studied. These channels exhibited two activity modes denoted as spike-like (SL) and multiconductance (MC). In the absence of mechanical stimulation, acidification of the intracellular side of membrane patches from 7.2 to 6.2 reversibly increased the mean channel open time as well as the opening frequency in the SL mode. Channels in MC mode were activated by a pH(i) reduction from 7.2 to 6.2, but were inhibited at pH(i) 5.5. Unlike MC mode, SL mode was strongly activated by intracellular Ca(2+). Fura-2 imaging experiments showed that intracellular calcium was induced to increase by hypotonic cell swelling. The major component of this response did not require extracellular calcium. A component of the swelling-induced calcium response was sensitive to blockers of stretch-sensitive cation channels. The results indicate that the two activity modes of mechanosensitive channels of leech neurons respond differently to changes of intracellular pH and calcium. The sensitivity of the channel to micromolar concentrations of internal free calcium, along with its permeability to this ion, is consistent with a role in the amplification of mechanically induced Ca(2+) signals in leech neurons.

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

Cited by 8 publications

References 13 publications

A mechanogated nonselective cation channel in proximal tubule that is ATP sensitive

A mechanogated nonselective cation channel in proximal tubule that is ATP sensitive

Mechanosensitive channels: feeling tension in a world under pressure

Effects of intracellular pH and Ca2+ on the activity of stretch-sensitive cation channels in leech neurons

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