Ether Anesthetics Obstructs Touch-Induced Trigger Hair Calcium-Electrical Signals Preventing Excitation of The Venus Flytrap

Abstract Plants do not have neurons. Instead they operate transmembrane ion channels and can be electrically excited by physical and chemical clues. The Venus flytrap with its distinctive hapto-electric signaling is a prime example. When an insect collides with the trigger hairs emerging from the inner surface of the trap, the mechanical stimulus in the mechanosensory organ is translated into a calcium signal and an action potential (AP). Here we asked how a Ca 2+ wave and AP are initiated in the trigger hair and how these are fed into the systemic trap calcium-electric network. When the Dionaea muscipula trigger hair matures and develops hapto-electric excitability, the mechanosensitive anion channel DmMSL10 and voltage dependent SKOR type Shaker K + channel are expressed in the shear stress-sensitive podium, which interfaces with the flytrap’s prey capture and processing networks. In the excitable state, touch stimulation of the trigger hair first evokes a rise in the podium Ca 2+ , then the calcium signal together with an action potential, travel over the entire trap surface. Seeking the mechanisms that mediate touch-induced Ca 2+ transients in the mature trigger hairs, we show that OSCA1.7 and GLR3.6 type Ca 2+ channels and ACA2/10 Ca 2+ pumps are specifically expressed in the podium. In addition, we found that direct glutamate application to the trap evoked a propagating Ca 2+ and electrical event. Given that anesthetics affect K + channels and glutamate receptors in animal systems, we exposed flytraps to ether. An ether atmosphere suppressed the propagation of touch and glutamate-induced Ca 2+ and AP long-distance signaling, a response that was completely recovered when ether was replaced by fresh air. In line with ether targeting a calcium channel, so triggering a Ca 2+ activated anion channel, the AP amplitude declined before the electrical signal ceased completely. Ether in the mechanosensory organ neither prevented the touch induction of a calcium signal nor its post stimulus decay. This finding indicates that ether prevents the touch activated GLR3.6-expressing base of the trigger hair so exciting the capture organ.

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Ether anesthetics prevents touch-induced trigger hair calcium-electrical signals excite the Venus flytrap

10.1101/2021.08.18.456873 ◽

2021 ◽

Author(s):

Soenke Scherzer ◽

Shouguang Huang ◽

Anda Iosip ◽

Ines Fuchs ◽

Ken Yokawa ◽

...

Keyword(s):

Ion Channels ◽

Action Potential ◽

Prey Capture ◽

Anion Channel ◽

Electrical Signal ◽

K Channel ◽

Calcium Signal ◽

Electrical Networks ◽

Long Distance ◽

Venus Flytrap

Plants do not have neurons but operate transmembrane ion channels and can get electrical excited by physical and chemical clues. Among them the Venus flytrap is characterized by its peculiar hapto-electric signaling. When insects collide with trigger hairs emerging the trap inner surface, the mechanical stimulus within the mechanosensory organ is translated into a calcium signal and an action potential (AP). Here we asked how the Ca2+ wave and AP is initiated in the trigger hair and how it is feed into systemic trap calcium-electrical networks. When Dionaea muscipula trigger hairs matures and develop hapto-electric excitability the mechanosensitive anion channel DmMSL10/FLYC1 and voltage dependent SKOR type Shaker K+ channel are expressed in the sheering stress sensitive podium. The podium of the trigger hair is interface to the flytrap`s prey capture and processing networks. In the excitable state touch stimulation of the trigger hair evokes a rise in the podium Ca2+ first and before the calcium signal together with an action potential travel all over the trap surface. In search for podium ion channels and pumps mediating touch induced Ca2+ transients, we, in mature trigger hairs firing fast Ca2+ signals and APs, found OSCA1.7 and GLR3.6 type Ca2+ channels and ACA2/10 Ca2+ pumps specifically expressed in the podium. Like trigger hair stimulation, glutamate application to the trap directly evoked a propagating Ca2+ and electrical event. Given that anesthetics affect K+ channels and glutamate receptors in the animal system we exposed flytraps to an ether atmosphere. As result propagation of touch and glutamate induced Ca2+ and AP long-distance signaling got suppressed, while the trap completely recovered excitability when ether was replaced by fresh air. In line with ether targeting a calcium channel addressing a Ca2+ activated anion channel the AP amplitude declined before the electrical signal ceased completely. Ether in the mechanosensory organ did neither prevent the touch induction of a calcium signal nor this post stimulus decay. This finding indicates that ether prevents the touch activated, glr3.6 expressing base of the trigger hair to excite the capture organ.

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Mechanical Signaling in the Sensitive Plant Mimosa pudica L.

Plants ◽

10.3390/plants9050587 ◽

2020 ◽

Vol 9 (5) ◽

pp. 587 ◽

Cited By ~ 5

Author(s):

Takuma Hagihara ◽

Masatsugu Toyota

Keyword(s):

Action Potential ◽

Plant Species ◽

Mechanical Stimulation ◽

Turgor Pressure ◽

Water Flux ◽

Electrical Signal ◽

Mimosa Pudica ◽

Spatial And Temporal Patterns ◽

Long Distance ◽

Motor Cells

As sessile organisms, plants do not possess the nerves and muscles that facilitate movement in most animals. However, several plant species can move quickly in response to various stimuli (e.g., touch). One such plant species, Mimosa pudica L., possesses the motor organ pulvinus at the junction of the leaflet-rachilla, rachilla-petiole, and petiole-stem, and upon mechanical stimulation, this organ immediately closes the leaflets and moves the petiole. Previous electrophysiological studies have demonstrated that a long-distance and rapid electrical signal propagates through M. pudica in response to mechanical stimulation. Furthermore, the spatial and temporal patterns of the action potential in the pulvinar motor cells were found to be closely correlated with rapid movements. In this review, we summarize findings from past research and discuss the mechanisms underlying long-distance signal transduction in M. pudica. We also propose a model in which the action potential, followed by water flux (i.e., a loss of turgor pressure) in the pulvinar motor cells is a critical step to enable rapid movement.

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Vorsicht, Verwundung! Reizweiterleitung mit mechanosensitiven Proteinen

BIOspektrum ◽

10.1007/s12268-021-1658-5 ◽

2021 ◽

Vol 27 (6) ◽

pp. 601-603

Author(s):

Michael M. Wudick

Keyword(s):

Experimental Evidence ◽

Anion Channel ◽

Signal Propagation ◽

Membrane Depolarization ◽

Electrical Signal ◽

Ion Fluxes ◽

Long Distance ◽

Wound Signaling ◽

Electric Signals

AbstractBeing sessile, plants are exposed to adverse stresses, including wounding by insects. Albeit lacking experimental evidence, one hypothesis predicted involvement of hydro-electric signals in wound signaling. Now, we could show that the mechanosensitive anion channel MSL10 is necessary for wound-induced long-distance signaling in plants. By linking mechano-sensing, ion fluxes, membrane depolarization and electrical signal propagation, MSL10 might integrate hydraulic and electric wound signals.

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A Theoretical Analysis of Relations between Pressure Changes along Xylem Vessels and Propagation of Variation Potential in Higher Plants

Plants ◽

10.3390/plants10020372 ◽

2021 ◽

Vol 10 (2) ◽

pp. 372

Author(s):

Ekaterina Sukhova ◽

Elena Akinchits ◽

Sergey V. Gudkov ◽

Roman Y. Pishchalnikov ◽

Vladimir Vodeneev ◽

...

Keyword(s):

Higher Plants ◽

Initial Point ◽

Electrical Signal ◽

Terminal Point ◽

Hydraulic Pressure ◽

Long Distance ◽

Variation Potential ◽

Damaged Zone ◽

Pressure Dynamics ◽

The Impact

Variation potential (VP) is an important long-distance electrical signal in higher plants that is induced by local damages, influences numerous physiological processes, and participates in plant adaptation to stressors. The transmission of increased hydraulic pressure through xylem vessels is the probable mechanism of VP propagation in plants; however, the rates of the pressure transmission and VP propagation can strongly vary. We analyzed this problem on the basis of a simple mathematical model of the pressure distribution along a xylem vessel, which was approximated by a tube with a pressure gradient. It is assumed that the VP is initiated if the integral over pressure is more than a threshold one, taking into account that the pressure is transiently increased in the initial point of the tube and is kept constant in the terminal point. It was shown that this simple model can well describe the parameters of VP propagation in higher plants, including the increase in time before VP initiation and the decrease in the rate of VP propagation with an increase in the distance from the zone of damage. Considering three types of the pressure dynamics, our model predicts that the velocity of VP propagation can be stimulated by an increase in the length of a plant shoot and also depends on pressure dynamics in the damaged zone. Our results theoretically support the hypothesis about the impact of pressure variations in xylem vessels on VP propagation.

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Action potentials induce biomagnetic fields in carnivorous Venus flytrap plants

Scientific Reports ◽

10.1038/s41598-021-81114-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Anne Fabricant ◽

Geoffrey Z. Iwata ◽

Sönke Scherzer ◽

Lykourgos Bougas ◽

Katharina Rolfs ◽

...

Keyword(s):

Electrical Activity ◽

Action Potentials ◽

Plant Stress ◽

Optically Pumped ◽

Long Distance ◽

Noninvasive Diagnostics ◽

Venus Flytrap ◽

Dionaea Muscipula ◽

Cell Arrays ◽

Electrical Signaling

AbstractUpon stimulation, plants elicit electrical signals that can travel within a cellular network analogous to the animal nervous system. It is well-known that in the human brain, voltage changes in certain regions result from concerted electrical activity which, in the form of action potentials (APs), travels within nerve-cell arrays. Electro- and magnetophysiological techniques like electroencephalography, magnetoencephalography, and magnetic resonance imaging are used to record this activity and to diagnose disorders. Here we demonstrate that APs in a multicellular plant system produce measurable magnetic fields. Using atomic optically pumped magnetometers, biomagnetism associated with electrical activity in the carnivorous Venus flytrap, Dionaea muscipula, was recorded. Action potentials were induced by heat stimulation and detected both electrically and magnetically. Furthermore, the thermal properties of ion channels underlying the AP were studied. Beyond proof of principle, our findings pave the way to understanding the molecular basis of biomagnetism in living plants. In the future, magnetometry may be used to study long-distance electrical signaling in a variety of plant species, and to develop noninvasive diagnostics of plant stress and disease.

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Abstract 14201: The Application of Hipsc-derived Cardiomyocytes Paced by Re-entrant Waves for Drug Assessment

Circulation ◽

10.1161/circ.142.suppl_3.14201 ◽

2020 ◽

Vol 142 (Suppl_3) ◽

Author(s):

Junjun Li ◽

Itsunari Minami ◽

Shigeru Miyagawa ◽

Xiang Qu ◽

YING HUA ◽

...

Keyword(s):

Cardiac Tissue ◽

Troponin T ◽

Field Potential ◽

Electrical Signal ◽

Assessment System ◽

K Channel ◽

Control Group ◽

Culture Dish ◽

Robust Response

Introduction: How to precisely evaluate response in newly developed medications in vitro may be a great concern in drug screening. We modified normal low-attachment culture dish and created closed-loop tissue ring from single hiPSC-CMs. We hypothesized that the re-entrant wave (ReW) could originate and pace the cardiac tissue ring, and the CMs under pacing could be matured and used for drug assessment. Methods: PDMS wells and pillars were mounted in low-attachment petri dishes (Figure 1A). 4 х 10 5 hiPSC-CMs were plated into the wells to form tissue ring where the ReW could spontaneously originate. After cultivation for 14 days, the hiPSC-CMs were evaluated by immunostaining and gene expression. Micro electrode array (MEA) were used to evaluating the CM response to different drugs. Results: The electrical signal recorded by MEA indicated that the ReWs could make the CMs beat at a much higher rate than the Control group (Figure 1B, 123.26 ± 10.36 bpm vs. 14.08 ± 4.53 bpm, p<0.0001). After 14 day culture, the ReW group demonstrated significantly higher expression of Troponin T (TnT2), myosin heavy chain 7 (β-MHC), and α-actinin. Interestingly, the α-actinin staining indicated alignment of CMs within the ReW group (Figure 1C). The CMs under ReW pacing showed robust response to several cardiac compounds including E4031, (hERG K+ channel blocker, Figure 1D and E), isoproterenol (β adrenoceptor agonist) and propranolol (beta-blocker). Both the field potential as well as the Ca 2+ transients showed correlated dose-dependent change and the recovering after washout of the drugs. Conclusions: The ReWs could spontaneously originate in the cultured cardiac tissue ring with enhancement of the maturation in the hiPSC-CMs and robust response to various drugs, indicating the system as a robust drug assessment system with multiple read-out methods.

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Action Potential and Contraction of Dionaea muscipula (Venus Flytrap)

Science ◽

10.1126/science.133.3456.878 ◽

1961 ◽

Vol 133 (3456) ◽

pp. 878-879 ◽

Cited By ~ 20

Author(s):

J. R. Di Palma ◽

R. Mohl ◽

W. Best

Keyword(s):

Action Potential ◽

Venus Flytrap ◽

Dionaea Muscipula

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Ionic channels in corneal endothelium

AJP Cell Physiology ◽

10.1152/ajpcell.1996.270.4.c975 ◽

1996 ◽

Vol 270 (4) ◽

pp. C975-C989 ◽

Cited By ~ 21

Author(s):

J. L. Rae ◽

M. A. Watsky

Keyword(s):

Patch Clamp ◽

Corneal Endothelium ◽

Single Channel ◽

Cell Voltage ◽

Anion Channel ◽

Ionic Channels ◽

K Channel ◽

Na Channel ◽

Channel Blockers ◽

K Currents

Single-channel patch-clamp techniques as well as standard and perforated-patch whole cell voltage-clamp techniques have been applied to the study of ionic channels in the corneal endothelium of several species. These studies have revealed two major K+ currents. One is due to an anion- and temperature-stimulated channel that is blocked by Cs+ but not by most other K+ channel blockers, and the other is similar to the family of A-currents found in excitable cells. The A-current is transient after a depolarizing voltage step and is blocked by both 4-aminopyridine and quinidine. These two currents are probably responsible for setting the -50 to -60 mV resting voltage reported for these cells. A Ca(2+)-activated ATP-inhibited nonselective cation channel and a tetrodotoxin-blocked Na+ channel are possible Na+ inflow pathways, but, given their gating properties, it is not certain that either channel works under physiological conditions. A large-conductance anion channel has also been identified by single-channel patch-clamp techniques. Single corneal endothelial cells have input resistances of 5-10 G omega and have steady-state K+ currents that are approximately 10 pA at the resting voltage. Pairs or monolayers of cells are electrically coupled and dye coupled through gap junctions.

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Effects of Na+ and K+ channel blockade on vulnerability to and termination of fibrillation in simulated normal cardiac tissue

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00241.2005 ◽

2005 ◽

Vol 289 (4) ◽

pp. H1692-H1701 ◽

Cited By ~ 29

Author(s):

Zhilin Qu ◽

James N. Weiss

Keyword(s):

Action Potential ◽

Cardiac Tissue ◽

Theoretical Perspective ◽

Conduction Block ◽

Dynamical Instability ◽

K Channel ◽

Channel Blockade ◽

Wave Instability ◽

Transient Time ◽

Underlying Mechanisms

Na+ and K+ channel-blocking drugs have anti- and proarrhythmic effects. Their effects during fibrillation, however, remain poorly understood. We used computer simulation of a two-dimensional (2-D) structurally normal tissue model with phase I of the Luo-Rudy action potential model to study the effects of Na+ and K+ channel blockade on vulnerability to and termination of reentry in simulated multiple-wavelet and mother rotor fibrillation. Our main findings are as follows: 1) Na+ channel blockade decreased, whereas K+ channel blockade increased, the vulnerable window of reentry in heterogeneous 2-D tissue because of opposing effects on dynamical wave instability. 2) Na+ channel blockade increased the cycle length of reentry more than it increased refractoriness. In multiple-wavelet fibrillation, Na+ channel blockade first increased and then decreased the average duration or transient time (<Ts>) of fibrillation. In mother rotor fibrillation, Na+ channel blockade caused peripheral fibrillatory conduction block to resolve and the mother rotor to drift, leading to self-termination or sustained tachycardia. 3) K+ channel blockade increased dynamical instability by steepening action potential duration restitution. In multiple-wavelet fibrillation, this effect shortened <Ts> because of enhanced wave instability. In mother rotor fibrillation, this effect converted mother rotor fibrillation to multiple-wavelet fibrillation, which then could self-terminate. Our findings help illuminate, from a theoretical perspective, the possible underlying mechanisms of termination of different types of fibrillation by antiarrhythmic drugs.

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