Dependence of membrane conductance ofLimulus ventral nerve photoreceptor on Ca2+/Na+-binding competition

1980 ◽  
Vol 6 (S1) ◽  
pp. 127-127
Author(s):  
H. Stieve ◽  
M. Pflaum ◽  
J. Klomfa\
Keyword(s):  
Membrane Conductance ◽  
Binding Competition ◽  
Ventral Nerve Photoreceptor

Disturbing Gtp-Binding Protein Function Through Microinjection Into The Visual Cell Of Limulus

1992 ◽  
Vol 47 (11-12) ◽  
pp. 915-921 ◽  
Author(s):  
Henmg Stieve ◽  
Barbara Niemeyer ◽  
Klaus Aktories ◽  
Heidi E. Hamm
Keyword(s):  
Monoclonal Antibody ◽  
G Protein ◽  
Protein Function ◽  
Clostridium Botulinum ◽  
Functional Role ◽  
Electrical Response ◽  
Visual Cell ◽  
Gtp Binding ◽  
Dim Light ◽  
Ventral Nerve Photoreceptor

We have tested the action of three agents microinjected into the ventral nerve photoreceptor of Limulus on the electrical response to dim light. 1. A monoclonal antibody (mAb 4 A) against the Gɑ subunit of frog transducin reduces the size of the receptor current to 60%, suggesting an interaction with Gɑ in the Limulus photoreceptor. 2. Injection of Clostridium botulinum ADPribosyltransferase C 3 reduces the size to 46%; latency is not affected. The results imply that small GTP-binding proteins play a functional role in photoreception of invertebrates. 3. Injection of GD P-β-S reduces dose-dependently the size of the receptor current to 15% and prolongs the latency to 200%, presumably by reducing number and rate of G-protein activations

Chemical Probes for Drug-Resistance Assessment by Binding Competition (RABC): Oseltamivir Susceptibility Evaluation

2012 ◽  
Vol 52 (1) ◽  
pp. 366-370 ◽  
Author(s):  
Ting-Jen R. Cheng ◽  
Shi-Yun Wang ◽  
Wen-Hsien Wen ◽  
Ching-Yao Su ◽  
Mengi Lin ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Chemical Probes ◽  
Binding Competition ◽  
Resistance Assessment ◽  
Susceptibility Evaluation

scholarly journals The molecular identity of the characean OH− transporter: a candidate related to the SLC4 family of animal pH regulators

PROTOPLASMA ◽  
2021 ◽  
Author(s):  
Bianca N. Quade ◽  
Mark D. Parker ◽  
Marion C. Hoepflinger ◽  
Shaunna Phipps ◽  
Mary A. Bisson ◽  
...  
Keyword(s):  
Inorganic Carbon ◽  
Membrane Conductance ◽  
Resting Potential ◽  
Large Scatter ◽  
Intrinsic Variability ◽  
Molecular Identity ◽  
Ph Banding ◽  
Chara Australis ◽  
Ph Increase ◽  
External Ph

AbstractCharaceae are closely related to the ancient algal ancestors of all land plants. The long characean cells display a pH banding pattern to facilitate inorganic carbon import in the acid zones for photosynthetic efficiency. The excess OH−, generated in the cytoplasm after CO2 is taken into the chloroplasts, is disposed of in the alkaline band. To identify the transporter responsible, we searched the Chara australis transcriptome for homologues of mouse Slc4a11, which functions as OH−/H+ transporter. We found a single Slc4-like sequence CL5060.2 (named CaSLOT). When CaSLOT was expressed in Xenopus oocytes, an increase in membrane conductance and hyperpolarization of resting potential difference (PD) was observed with external pH increase to 9.5. These features recall the behavior of Slc4a11 in oocytes and are consistent with the action of a pH-dependent OH−/H+ conductance. The large scatter in the data might reflect intrinsic variability of CaSLOT transporter activation, inefficient expression in the oocyte due to evolutionary distance between ancient algae and frogs, or absence of putative activating factor present in Chara cytoplasm. CaSLOT homologues were found in chlorophyte and charophyte algae, but surprisingly not in related charophytes Zygnematophyceae or Coleochaetophyceae.

Is cyclic guanosine monophosphate the internal 'second messenger' for cholinergic actions on central neurons?

1976 ◽  
Vol 54 (2) ◽  
pp. 172-176 ◽  
Author(s):  
K. Krnjević ◽  
E. Puil ◽  
R. Werman
Keyword(s):  
Time Course ◽  
Membrane Conductance ◽  
Cyclic Guanosine Monophosphate ◽  
Guanosine Monophosphate ◽  
Resting Potential ◽  
Electrical Excitability ◽  
Spinal Motoneurons ◽  
Central Neurons ◽  
Intracellular Cgmp ◽  
Post Synaptic Potential

The most consistent effects produced by intracellular injections of guanosine 3′,5′-cyclic monophosphate (cGMP) (but not 5′-guanosine 5′-monophosphate in spinal motoneurons of cats are a rise in membrane conductance, acceleration in time course of spike potentials, and accentuation of the post-spike hyperpolarization. Associated changes in resting potential are smaller, less constant, and more often in the depolarizing than hyperpolarizing direction. cGMP tends to increase electrical excitability but reduces excitatory post-synaptic potential amplitudes. Most of the effects of intracellular cGMP are quite different from, or indeed opposite to, those of either extra- or intracellular applications of acetylcholine and therefore not consistent with the proposal that cGMP is the internal mediator of muscarinic actions.

Immunoglobulin E mediated membrane conductance changes in rat basophilic leukemia cells

1988 ◽  
Vol 66 (3) ◽  
pp. 328-331 ◽  
Author(s):  
Carlos Barajas-López ◽  
Jan D. Huizinga
Keyword(s):  
Immunoglobulin E ◽  
Calcium Influx ◽  
Membrane Conductance ◽  
Membrane Resistance ◽  
Leukemia Cells ◽  
Rat Basophilic Leukemia Cells ◽  
Conductance Changes ◽  
Electrophysiological Effects ◽  
Basophilic Leukemia ◽  
Stimulation Of

Electrophysiological effects of anaphylactic stimulation of rat basophilic leukemia cells (RBL-2H3) were studied using conventional microelectrodes. Stimulation of passively sensitized cells by anti-immunoglobulin E resulted in hyperpolarization followed by depolarization. These changes in membrane polarization were associated with a decrease in input membrane resistance. No effect of anaphylactic stimulation was seen in Ca2+-free solution or when Ca2+ influx was blocked by Co2+, but it was mimicked by the Ca2+ ionophore A-23187. This suggests that the changes in ionic conductances were associated with calcium influx. These results support the hypothesis that membrane conductance changes are involved in the stimulus-secretion process of the RBL-2H3 cells.

scholarly journals Membrane Currents in Airway Smooth Muscle: Mechanisms and Therapeutic Implications

1997 ◽  
Vol 4 (1) ◽  
pp. 13-20
Author(s):  
Luke J Janssen
Keyword(s):  
Smooth Muscle ◽  
Ion Channels ◽  
Calcium Channels ◽  
Airway Smooth Muscle ◽  
Calcium Ion ◽  
Membrane Conductance ◽  
Chloride Ion ◽  
Potassium Ion Channels ◽  
Therapeutic Implications ◽  
Transient Activation

Electrophysiological and pharmacological techniques were used to characterize the membrane conductance changes underlying spasmogen-evoked depolarization in airway smooth muscle (ASM). Changes included a transient activation of chloride ion channels and prolonged suppression of potassium ion channels; both changes are triggered by release of internally sequestered calcium ion and in turn cause opening of voltage-dependent calcium channels. The resultant influx of calcium ions contributes to contraction as well as to refilling of the internal calcium ion pool. Bronchodilators, on the other hand, act in part through activation of potassium channels, with consequent closure of calcium channels. The tools used to study ion channels in ASM are described, and the investigations of the roles of ion channels in ASM physiology (autacoid-evoked depolarization and hyperpolarization) and pathophysiology (airway hyperresponsiveness) are summarized. Finally, how the relationship between ion channels and ASM function/dysfunction may relate to the treatment of asthma and related breathing disorders is discussed.

scholarly journals Effects of Vpu Expression onXenopusOocyte Membrane Conductance

Virology ◽  
1998 ◽  
Vol 244 (1) ◽  
pp. 39-49 ◽  
Author(s):  
Michael J. Coady ◽  
Nash G. Daniel ◽  
Evangelos Tiganos ◽  
Béatrice Allain ◽  
Jacques Friborg ◽  
...  
Keyword(s):  
Membrane Conductance
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