 |
 Previous Article | Next Article 
The Journal of Neuroscience, November 1, 1998, 18(21):8740-8750
Differences in Ca2+ Channels Governing Generation of
Miniature and Evoked Excitatory Synaptic Currents in Spinal Laminae I
and II
Juping
Bao,
Jing James
Li, and
Edward R.
Perl
Department of Cell and Molecular Physiology, University of
North Carolina-Chapel Hill, Chapel Hill, North Carolina 27599-7545
Many neurons of spinal laminae I and II, a region concerned with
pain and other somatosensory mechanisms, display frequent miniature
"spontaneous" EPSCs (mEPSCs). In a number of instances, mEPSCs
occur often enough to influence neuronal excitability. To compare
generation of mEPSCs to EPSCs evoked by dorsal root stimulation
(DR-EPSCs), various agents affecting neuronal activity and
Ca2+ channels were applied to in
vitro slice preparations of rodent spinal cord during
tight-seal, whole-cell, voltage-clamp recordings from laminae I and II
neurons. The AMPA/kainate glutamate receptor antagonist CNQX (10-20
µM) regularly abolished DR-EPSCs. In many neurons CNQX
also eliminated mEPSCs; however, in a number of cases a proportion of
the mEPSCs were resistant to CNQX suggesting that in these instances
different mediators or receptors were also involved.
Cd2+ (10-50 µM) blocked evoked EPSCs
without suppressing mEPSC occurrence. In contrast,
Ni2+ ( 100 µM), a low-threshold
Ca2+ channel antagonist, markedly decreased mEPSC
frequency while leaving evoked monosynaptic EPSCs little changed.
Selective organic antagonists of high-threshold (HVA)
Ca2+ channels, nimodipine,  -Conotoxin GVIA, and
Agatoxin IVA partially suppressed DR-EPSCs, however, they had little or
no effect on mEPSC frequency. La3+ and mibefradil,
agents interfering with low-threshold Ca2+ channels,
regularly decreased mEPSC frequency with little effect on fast-evoked
EPSCs. Increased [K+]o (5-10
mM) in the superfusion, producing modest depolarizations, consistently increased mEPSC frequency; an increase suppressed by
mibefradil but not by HVA Ca2+ channel antagonists.
Together these observations indicate that different
Ca2+ channels are important for evoked EPSCs and
mEPSCs in spinal laminae I and II and implicate a low-threshold type of
Ca2+ channel in generation of mEPSCs.
Key words:
mEPSCs; EPSCs; LVA Ca2+ channels; spinal laminae I and II; spinal dorsal horn; rodent; mibefradil; La3+
Copyright © 1998 Society for Neuroscience 0270-6474/98/18218740-11$05.00/0
This article has been cited by other articles:
|
|
|
|
 
Y. V. Medvedeva, M.-S. Kim, and Y. M. Usachev
Mechanisms of Prolonged Presynaptic Ca2+ Signaling and Glutamate Release Induced by TRPV1 Activation in Rat Sensory Neurons
J. Neurosci.,
May 14, 2008;
28(20):
5295 - 5311.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
V. Pinto, V. A. Derkach, and B. V. Safronov
Role of TTX-Sensitive and TTX-Resistant Sodium Channels in A{delta}- and C-Fiber Conduction and Synaptic Transmission
J Neurophysiol,
February 1, 2008;
99(2):
617 - 628.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
B. K. Rycroft, K. S. Vikman, and M. J. Christie
Inflammation reduces the contribution of N-type calcium channels to primary afferent synaptic transmission onto NK1 receptor-positive lamina I neurons in the rat dorsal horn
J. Physiol.,
May 1, 2007;
580(3):
883 - 894.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
D. D. Kline, A. Ramirez-Navarro, and D. L. Kunze
Adaptive Depression in Synaptic Transmission in the Nucleus of the Solitary Tract after In Vivo Chronic Intermittent Hypoxia: Evidence for Homeostatic Plasticity
J. Neurosci.,
April 25, 2007;
27(17):
4663 - 4673.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J.-K. Cheng, C.-C. Chen, J.-R. Yang, and L.-C. Chiou
The Antiallodynic Action Target of Intrathecal Gabapentin: Ca2+ Channels, KATP Channels or N-Methyl-d-Aspartic Acid Receptors?
Anesth. Analg.,
January 1, 2006;
102(1):
182 - 187.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. Cordero-Erausquin, J. A. M. Coull, D. Boudreau, M. Rolland, and Y. D. Koninck
Differential Maturation of GABA Action and Anion Reversal Potential in Spinal Lamina I Neurons: Impact of Chloride Extrusion Capacity
J. Neurosci.,
October 19, 2005;
25(42):
9613 - 9623.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
A. Dahlhaus, R. Ruscheweyh, and J. Sandkuhler
Synaptic input of rat spinal lamina I projection and unidentified neurones in vitro
J. Physiol.,
July 15, 2005;
566(2):
355 - 368.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
H. Chen and S. R. Ikeda
Modulation of Ion Channels and Synaptic Transmission by a Human Sensory Neuron-Specific G-Protein-Coupled Receptor, SNSR4/mrgX1, Heterologously Expressed in Cultured Rat Neurons
J. Neurosci.,
May 26, 2004;
24(21):
5044 - 5053.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
Y.-C. Liang, C.-C. Huang, K.-S. Hsu, and T. Takahashi
Cannabinoid-induced presynaptic inhibition at the primary afferent trigeminal synapse of juvenile rat brainstem slices
J. Physiol.,
February 15, 2004;
555(1):
85 - 96.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
S. Wang, Z. Jia, J. Roder, and T. H. Murphy
AMPA Receptor-Mediated Miniature Synaptic Calcium Transients in GluR2 Null Mice
J Neurophysiol,
July 1, 2002;
88(1):
29 - 40.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
F.-M. Lu and K. Kuba
Synchronous and Asynchronous Exocytosis Induced by Subthreshold High K+ at Cs+-Loaded Terminals of Rat Hippocampal Neurons
J Neurophysiol,
March 1, 2002;
87(3):
1222 - 1233.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
Y.-F. Wang, X.-B. Gao, and A. N. van den Pol
Membrane Properties Underlying Patterns of GABA-Dependent Action Potentials in Developing Mouse Hypothalamic Neurons
J Neurophysiol,
September 1, 2001;
86(3):
1252 - 1265.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
T. P. Wong, G. Marchese, M. A. Casu, A. Ribeiro-da-Silva, A. C. Cuello, and Y. De Koninck
Loss of Presynaptic and Postsynaptic Structures Is Accompanied by Compensatory Increase in Action Potential-Dependent Synaptic Input to Layer V Neocortical Pyramidal Neurons in Aged Rats
J. Neurosci.,
November 15, 2000;
20(22):
8596 - 8606.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
A. Ito, E. Kumamoto, M. Takeda, M. Takeda, K. Shibata, H. Sagai, and M. Yoshimura
Mechanisms for Ovariectomy-Induced Hyperalgesia and Its Relief by Calcitonin: Participation of 5-HT1A-Like Receptor on C-Afferent Terminals in Substantia Gelatinosa of the Rat Spinal Cord
J. Neurosci.,
August 15, 2000;
20(16):
6302 - 6308.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
H. U. Zeilhofer, U. M. Selbach, H. Guhring, K. Erb, and S. Ahmadi
Selective Suppression of Inhibitory Synaptic Transmission by Nocistatin in the Rat Spinal Cord Dorsal Horn
J. Neurosci.,
July 1, 2000;
20(13):
4922 - 4929.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
S. B. Kombian, M. Hirasawa, D. Mouginot, X. Chen, and Q. J. Pittman
Short-Term Potentiation of Miniature Excitatory Synaptic Currents Causes Excitation of Supraoptic Neurons
J Neurophysiol,
May 1, 2000;
83(5):
2542 - 2553.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
A. R. Light and H. H. Willcockson
Spinal Laminae I-II Neurons in Rat Recorded In Vivo in Whole Cell, Tight Seal Configuration: Properties and Opioid Responses
J Neurophysiol,
December 1, 1999;
82(6):
3316 - 3326.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
O. Prange and T. H. Murphy
Correlation of Miniature Synaptic Activity and Evoked Release Probability in Cultures of Cortical Neurons
J. Neurosci.,
August 1, 1999;
19(15):
6427 - 6438.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
T. J. Grudt and E. R. Perl
Correlations between neuronal morphology and electrophysiological features in the rodent superficial dorsal horn
J. Physiol.,
April 1, 2002;
540(1):
189 - 207.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
