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NMDA-induced burst discharge in guinea pig trigeminal motoneurons in vitro.
J Neurophysiol. 1995 Jul; 74(1):334-46.JN

Abstract

1. The responses of guinea pig trigeminal motoneurons (TMNs) to N-methyl-D,L-aspartate (NMA) were studied using brain stem slice preparations and whole cell patch-clamp (n = 89) or conventional microelectrode (n = 22) recording techniques. The primary goals of this study were to determine whether N-methyl-D-aspartate (NMDA) receptor activation would produce spontaneous bursting activity in TMNs and, if so, the underlying mechanisms responsible for the generation of these bursts. 2. Bath-applied NMA (100-300 microM, n = 80) in standard perfusion medium elicited depolarization, increase in apparent input resistance (Rinp), and rhythmic burst discharges (1-90 s in duration) from TMNs. These effects were blocked by the NMDA receptor antagonist DL-2-amino-5-phosphonopentanoic acid (AP5, 30 microM, n = 6), but not by the non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 5-10 microM, n = 10). Furthermore, the burst-inducing effect of NMA was not mimicked by the non-NMDA receptor agonists kainate (KA, 5-10 microM, n = 6) and (+/-)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA, 5-10 microM, n = 5). 3. In tetrodotoxin (TTX) treatment conditions (n = 13), NMA elicited depolarization, an increase in apparent Rinp, and rhythmic membrane potential oscillations without action potential bursts (i.e., plateau potentials), suggesting that the effects of NMA observed in the TTX-free condition resulted from activation of postsynaptic NMDA receptors. 4. Graded depolarization of neurons (n = 20) by intracellular direct current injection generally led to a graded increase in frequency and duration of the NMA-induced bursts and plateau potentials until these rhythmic events eventually became transformed into continuous spike discharge and maintained depolarization, respectively. Removal of Mg2+ from the perfusion medium (n = 11) also turned the bursts and plateau potentials into continuous spike discharge and maintained depolarization, respectively. 5. The effects of NMA on the current-voltage (I-V) curve after a depolarizing ramp voltage-clamp command (15-20 mV/s) were examined (n = 40). Under NMA (100-300 microM) conditions, the I-V relationship exhibited a region of negative slope conductance (NSC) between -60 and -35 mV, thus making the I-V relationship N-shaped. The NSC was abolished by AP5 (30 microM, n = 8), but not by CNQX (5-10 microM, n = 6). The I-V relationship in AMPA (3-10 microM, n = 5) or KA (3-10 microM, n = 5) was almost linear between -80 and -30 mV.(

ABSTRACT

TRUNCATED AT 400 WORDS)

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Authors+Show Affiliations

Kim YI
Department of Physiological Science, University of California at Los Angeles 90024, USA.
Chandler SH
No affiliation info available

MeSH

2-Amino-5-phosphonovalerateAnimalsElectrophysiologyExcitatory Amino Acid AgonistsGuinea PigsIn Vitro TechniquesMagnesiumMaleMembrane PotentialsMicroelectrodesMotor NeuronsN-MethylaspartatePatch-Clamp TechniquesPotassium ChannelsReceptors, N-Methyl-D-AspartateTetrodotoxinTrigeminal Nerve

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

7472335

Citation

Kim, Y I., and S H. Chandler. "NMDA-induced Burst Discharge in Guinea Pig Trigeminal Motoneurons in Vitro." Journal of Neurophysiology, vol. 74, no. 1, 1995, pp. 334-46.
Kim YI, Chandler SH. NMDA-induced burst discharge in guinea pig trigeminal motoneurons in vitro. J Neurophysiol. 1995;74(1):334-46.
Kim, Y. I., & Chandler, S. H. (1995). NMDA-induced burst discharge in guinea pig trigeminal motoneurons in vitro. Journal of Neurophysiology, 74(1), 334-46.
Kim YI, Chandler SH. NMDA-induced Burst Discharge in Guinea Pig Trigeminal Motoneurons in Vitro. J Neurophysiol. 1995;74(1):334-46. PubMed PMID: 7472335.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - NMDA-induced burst discharge in guinea pig trigeminal motoneurons in vitro. AU - Kim,Y I, AU - Chandler,S H, PY - 1995/7/1/pubmed PY - 1995/7/1/medline PY - 1995/7/1/entrez SP - 334 EP - 46 JF - Journal of neurophysiology JO - J Neurophysiol VL - 74 IS - 1 N2 - 1. The responses of guinea pig trigeminal motoneurons (TMNs) to N-methyl-D,L-aspartate (NMA) were studied using brain stem slice preparations and whole cell patch-clamp (n = 89) or conventional microelectrode (n = 22) recording techniques. The primary goals of this study were to determine whether N-methyl-D-aspartate (NMDA) receptor activation would produce spontaneous bursting activity in TMNs and, if so, the underlying mechanisms responsible for the generation of these bursts. 2. Bath-applied NMA (100-300 microM, n = 80) in standard perfusion medium elicited depolarization, increase in apparent input resistance (Rinp), and rhythmic burst discharges (1-90 s in duration) from TMNs. These effects were blocked by the NMDA receptor antagonist DL-2-amino-5-phosphonopentanoic acid (AP5, 30 microM, n = 6), but not by the non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 5-10 microM, n = 10). Furthermore, the burst-inducing effect of NMA was not mimicked by the non-NMDA receptor agonists kainate (KA, 5-10 microM, n = 6) and (+/-)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA, 5-10 microM, n = 5). 3. In tetrodotoxin (TTX) treatment conditions (n = 13), NMA elicited depolarization, an increase in apparent Rinp, and rhythmic membrane potential oscillations without action potential bursts (i.e., plateau potentials), suggesting that the effects of NMA observed in the TTX-free condition resulted from activation of postsynaptic NMDA receptors. 4. Graded depolarization of neurons (n = 20) by intracellular direct current injection generally led to a graded increase in frequency and duration of the NMA-induced bursts and plateau potentials until these rhythmic events eventually became transformed into continuous spike discharge and maintained depolarization, respectively. Removal of Mg2+ from the perfusion medium (n = 11) also turned the bursts and plateau potentials into continuous spike discharge and maintained depolarization, respectively. 5. The effects of NMA on the current-voltage (I-V) curve after a depolarizing ramp voltage-clamp command (15-20 mV/s) were examined (n = 40). Under NMA (100-300 microM) conditions, the I-V relationship exhibited a region of negative slope conductance (NSC) between -60 and -35 mV, thus making the I-V relationship N-shaped. The NSC was abolished by AP5 (30 microM, n = 8), but not by CNQX (5-10 microM, n = 6). The I-V relationship in AMPA (3-10 microM, n = 5) or KA (3-10 microM, n = 5) was almost linear between -80 and -30 mV.(ABSTRACT TRUNCATED AT 400 WORDS) SN - 0022-3077 UR - https://www.unboundmedicine.com/medline/citation/7472335/NMDA_induced_burst_discharge_in_guinea_pig_trigeminal_motoneurons_in_vitro_ L2 - https://journals.physiology.org/doi/10.1152/jn.1995.74.1.334?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -