?-Grammotoxin blocks action-potential-induced Ca2+ influx and whole-cell Ca2+ current in rat dorsal-root ganglion neurons

1994 ◽  
Vol 426 (3-4) ◽  
pp. 214-220 ◽  
Author(s):  
T. M. Piser ◽  
R. A. Lampe ◽  
R. A. Keith ◽  
S. A. Thayer
Keyword(s):  
Dorsal Root Ganglion ◽  
Action Potential ◽  
Dorsal Root ◽  
Dorsal Root Ganglion Neurons ◽  
Whole Cell ◽  
Ganglion Neurons

GABA-Induced Cl− Current in Cultured Embryonic Human Dorsal Root Ganglion Neurons

1999 ◽  
Vol 82 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Alexander Y. Valeyev ◽  
John C. Hackman ◽  
Alice M. Holohean ◽  
Patrick M. Wood ◽  
Jennifer L. Katz ◽  
...  
Keyword(s):  
Dorsal Root Ganglion ◽  
Dorsal Root ◽  
Single Channel ◽  
Dorsal Root Ganglion Neurons ◽  
Hill Coefficient ◽  
Equilibrium Potential ◽  
Single Channels ◽  
Drg Neurons ◽  
Whole Cell ◽  
Ganglion Neurons

γ-Aminobutyric acid (GABA)-activated channels in embryonic (5–8 wk old) human dorsal root ganglion (DRG) neurons in dissociated culture were characterized by whole cell and single-channel techniques. All DRG neurons when held at negative holding membrane potentials displayed inward current to micromolar concentrations of GABA applied by pressure pulses from closely positioned micropipettes. The current was directly proportional to the concentration of GABA (EC50, 111 μM; Hill coefficient, 1.7). DRG neurons also responded to micromolar concentrations of pentobarbital and alphaxalone but not to cis-4-aminocrotonic acid (CACA), glycine, or taurine. Baclofen (100 μM) affected neither the holding currents nor K+ conductance (when patch pipettes were filled with 130 mM KCl) caused by depolarizing pulses. Whole cell GABA-currents were blocked by bicuculline, picrotoxin, and t-butylbicyclophosphorothionate (TBPS; all at 100 μM). The reversal potential of whole cell GABA-currents was close to the theoretical Cl− equilibrium potential, shifting with changes in intracellular Cl− concentration in a manner expected for Cl−-selective channels. The whole cell I-V curve for GABA-induced currents demonstrated slight outward rectification with nearly symmetrical outside and inside Cl− concentrations. Spectral analysis of GABA-induced membrane current fluctuations showed that the kinetic components were best fitted by a triple Lorentzian function. The apparent elementary conductance for GABA-activated Cl− channels determined from the power spectra was 22.6 pS. Single-channel recordings from cell-attached patches with pipettes containing 10 μM GABA indicated that GABA-activated channels have a main and a subconductance level with values of 30 and 19 pS, respectively. Mean open and closed times of the channel were characterized by two or three exponential decay functions, suggesting two or three open channel states and two closed states. Single channels showed a lack of rectification. The actions of GABA on cultured human embryonic DRG neurons are mediated through the activation of GABAA receptors with properties corresponding to those found in the CNS of human and other mammalian species but differing from those of cultured human adult DRG neurons.

Electrophysiological Analysis of Dorsal Root Ganglion Neurons Pre- and Post-Coexpression of Green Fluorescent Protein and Functional 5-HT3Receptor

1997 ◽  
Vol 77 (6) ◽  
pp. 3115-3121 ◽  
Author(s):  
George M. Smith ◽  
Richard L. Berry ◽  
Jay Yang ◽  
Darrell Tanelian
Keyword(s):  
Green Fluorescent Protein ◽  
Dorsal Root Ganglion ◽  
Dorsal Root ◽  
Fluorescent Protein ◽  
Dorsal Root Ganglion Neurons ◽  
Drg Neurons ◽  
Whole Cell ◽  
Electrophysiological Analysis ◽  
Green Fluorescent ◽  
Ganglion Neurons

Smith, George M., Richard L. Berry, Jay Yang, and Darrell Tanelian. Electrophysiological analysis of dorsal root ganglion neurons pre- and post-coexpression of green fluorescent protein and functional 5-HT3receptor. J. Neurophysiol. 77: 3115–3121, 1997. Aequorea green fluorescent protein (GFP) is an excellent marker to examine genetically altered live cells in whole animals or culture. Its potential use in identifying genetically modified neurons, however, has not been investigated extensively. To examine the usefulness, toxicity, and potential electrophyiological effects of GFP expression in neurons, we generated adenovirus containing the mGFP4 cDNA. One week after virus transfection of dorsal root ganglion neurons (DRG), 10% of postnatal DRG neurons appeared brightly fluorescent, labelling the soma and neurites. Temporal examination of these neurons demonstrated no toxicity to DRG neurons even after several weeks in culture with repeated daily epifluorescent exposure. Electrophysiological analysis and comparison of control and viral exposed (GFP− and GFP+) DRG neurons did not demonstrate any differences in whole cell resistance, resting potential, action potential (AP) threshold, AP duration, AP amplitude, or whole cell capacitance. To investigate the usefulness of GFP as a marker for identifying neurons genetically altered to express a novel neurotransmitter receptor, a second adenovirus construct was generated containing both GFP and serotonin type 3 (5-HT3) receptor cDNAs. Transfection of DRG neurons with this virus produced an inward current in the presence of serotonin only in DRG neurons that were GFP-positive. It is concluded that adenoviral transfection of neurons with GFP, for cellular labeling, and coexpression of GFP-neurotransmitter constructs are safe, nontoxic, methods for electrophysiologically investigating neurons over several weeks. The uniqueness of the vector used in these experiments is that it was constructed to express GFP in a second cassette so that it would label the transduced cells, but have no potential for interfering with the function of the foreign 5-HT3receptor.

Opioids reduce the peak amplitude of action potential in adult rat dorsal root ganglion neurons

2011 ◽  
Vol 71 ◽  
pp. e156-e157
Author(s):  
Kotaro Mizuta ◽  
Tsugumi Fujita ◽  
Chang-Yu Jiang ◽  
Hai-Yuan Yue ◽  
Masanari Inoue ◽  
...  
Keyword(s):  
Dorsal Root Ganglion ◽  
Action Potential ◽  
Dorsal Root ◽  
Dorsal Root Ganglion Neurons ◽  
Peak Amplitude ◽  
Adult Rat ◽  
Ganglion Neurons

Inflammatory Mediators Enhance the Excitability of Chronically Compressed Dorsal Root Ganglion Neurons

2006 ◽  
Vol 95 (4) ◽  
pp. 2098-2107 ◽  
Author(s):  
C. Ma ◽  
K. W. Greenquist ◽  
R. H. LaMotte
Keyword(s):  
Dorsal Root Ganglion ◽  
Action Potential ◽  
Inflammatory Mediators ◽  
Dorsal Root ◽  
Dorsal Root Ganglion Neurons ◽  
Resting Membrane Potential ◽  
Prostaglandin E ◽  
Drg Neurons ◽  
Neuronal Hyperexcitability ◽  
Ganglion Neurons

A laterally herniated disk, spinal stenosis, and various degenerative or traumatic diseases of the spine can sometimes lead to a chronic compression and inflammation of the dorsal root ganglion and chronic abnormal sensations including pain. After a chronic compression of the dorsal root ganglion (CCD) in rats, the somata in the dorsal root ganglion (DRG) become hyperexcitable, and some exhibit ectopic, spontaneous activity (SA). Inflammatory mediators have a potential role in modulating the excitability of DRG neurons and therefore may contribute to the neuronal hyperexcitability after CCD. In this study, an inflammatory soup (IS) consisting of bradykinin, serotonin, prostaglandin E2, and histamine (each 10−6M) was applied topically to the DRG. The responses of DRG neurons were electrophysiologically recorded extracellularly from teased dorsal root fibers or intracellularly from the somata in the intact DRG or from dissociated neurons within 30 h of culture. In all three preparations, IS remarkably increased the discharge rates of SA CCD neurons and evoked discharges in more silent-CCD than control neurons. IS slightly depolarized the resting membrane potential and decreased the current and voltage thresholds of action potential in both intact and dissociated neurons, although the magnitude of depolarization or decrease in action potential threshold was not significantly different between CCD and control. IS-evoked responses were found in a proportion of neurons in each size category including those with and without nociceptive properties. Inflammatory mediators, by increasing the excitability of DRG somata, may contribute to CCD-induced neuronal hyperexcitability and to hyperalgesia and tactile allodynia.

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