 |
 Previous Article | Next Article 
Volume 16, Number 16,
Issue of August 15, 1996
pp. 4971-4982
Copyright ©1996 Society for Neuroscience
Multiple Actions of 1S,3R-ACPD in Modulating Endogenous Synaptic
Transmission to Spinal Respiratory Motoneurons
Received Feb. 20, 1996; revised May 22, 1996; accepted May 28, 1996.
Xiao-Wei Dong1,
Didier Morin1, and
Jack L. Feldman1, 2
Systems Neurobiology Laboratory, Departments of
1 Physiological Science and 2 Neurobiology,
University of California at Los Angeles, Los Angeles, California
90095-1527
To determine physiological roles of metabotropic glutamate
receptors (mGluRs) affecting breathing, we examined the effects of
(1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid (1S,3R-ACPD) on
synaptic transmission and excitability of phrenic motoneurons (PMNs) in
an in vitro neonatal rat brainstem/spinal cord preparation.
The effects of 1S,3R-ACPD were multiple, including reduction of
inspiratory-modulated synaptic currents and increase of neuronal
excitability via an inward current (Iacpd)
associated with a decrease of membrane conductance. The mechanism
underlying synaptic depression was examined. We found that 1S,3R-ACPD
reduced the frequency but not the amplitude of miniature excitatory
postsynaptic currents. The current induced by exogenous AMPA was not
significantly affected by 1S,3R-ACPD. These results suggest that
1S,3R-ACPD-induced reduction of inspiratory synaptic currents is
mediated by presynaptic mGluRs. We also examined the ionic basis for
Iacpd. We found that
Iacpd had a reversal potential of
approximately  100 mV, close to the estimated
EK+ (95 mV). Elevating
extracellular [K+] to 9 mM reduced the Iacpd
reversal potential to 75 mV. The K+ channel blocker
Ba2+ induced an inward current with a
reversal potential at 93 mV associated with a decrease of membrane
conductance, closely resembling the effect of 1S,3R-ACPD. Moreover,
Ba2+ occluded 1S,3R-ACPD effects. In the presence
of Ba2+, Iacpd and
the 1S,3R-ACPD-induced decrease of membrane conductance were
diminished. Our data indicate that the dominant component of
Iacpd results from the blockade of a
Ba2+-sensitive resting K+
conductance. We conclude that the activation of mGluRs affects the
inspiratory-modulated activity of PMNs via distinct mechanisms at pre-
and postsynaptic sites.
Key words:
1S,3R-ACPD;
metabotropic glutamate receptors;
synaptic
transmission;
presynaptic;
excitability;
potassium channels;
brainstem;
spinal cord;
phrenic motoneurons;
respiration
This article has been cited by other articles:
|
|
|
|
 
S. Mironov
Respiratory Circuits: Function, Mechanisms, Topology, and Pathology
Neuroscientist,
April 1, 2009;
15(2):
194 - 208.
[Abstract]
[PDF]
|
|
|
|
|
|
|
E. K. Kosmidis, O. Pierrefiche, and J.-F. Vibert
Respiratory-Like Rhythmic Activity Can Be Produced by an Excitatory Network of Non-Pacemaker Neuron Models
J Neurophysiol,
August 1, 2004;
92(2):
686 - 699.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. Takahashi and S. Alford
The Requirement of Presynaptic Metabotropic Glutamate Receptors for the Maintenance of Locomotion
J. Neurosci.,
May 1, 2002;
22(9):
3692 - 3699.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
P. G. Guyenet, C. P. Sevigny, M. C. Weston, and R. L. Stornetta
Neurokinin-1 Receptor-Expressing Cells of the Ventral Respiratory Group Are Functionally Heterogeneous and Predominantly Glutamatergic
J. Neurosci.,
May 1, 2002;
22(9):
3806 - 3816.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
R. Donato and A. Nistri
Relative Contribution by GABA or Glycine to Cl--Mediated Synaptic Transmission on Rat Hypoglossal Motoneurons In Vitro
J Neurophysiol,
December 1, 2000;
84(6):
2715 - 2724.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
N. E. Schwartz and S. Alford
Physiological Activation of Presynaptic Metabotropic Glutamate Receptors Increases Intracellular Calcium and Glutamate Release
J Neurophysiol,
July 1, 2000;
84(1):
415 - 427.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. C. Rekling, G. D. Funk, D. A. Bayliss, X.-W. Dong, and J. L. Feldman
Synaptic Control of Motoneuronal Excitability
Physiol Rev,
April 1, 2000;
80(2):
767 - 852.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
X.-W. Dong and J. L. Feldman
Distinct Subtypes of Metabotropic Glutamate Receptors Mediate Differential Actions on Excitability of Spinal Respiratory Motoneurons
J. Neurosci.,
July 1, 1999;
19(13):
5173 - 5184.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
C. A. Del Negro and S. H. Chandler
Regulation of Intrinsic and Synaptic Properties of Neonatal Rat Trigeminal Motoneurons by Metabotropic Glutamate Receptors
J. Neurosci.,
November 15, 1998;
18(22):
9216 - 9226.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. Kolaj and L. P. Renaud
Vasopressin-Induced Currents in Rat Neonatal Spinal Lateral Horn Neurons Are G-Protein Mediated and Involve Two Conductances
J Neurophysiol,
October 1, 1998;
80(4):
1900 - 1910.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
T. Aosaki, K. Kiuchi, and Y. Kawaguchi
Dopamine D1-Like Receptor Activation Excites Rat Striatal Large Aspiny Neurons In Vitro
J. Neurosci.,
July 15, 1998;
18(14):
5180 - 5190.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. Kolaj, S. J. Shefchyk, and L. P. Renaud
Two Conductances Mediate Thyrotropin-Releasing-Hormone-Induced Depolarization of Neonatal Rat Spinal Preganglionic and Lateral Horn Neurons
J Neurophysiol,
September 1, 1997;
78(3):
1726 - 1729.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
