Desensitization of AMPA receptors limits the amplitude of EPSPs and the excitability of motoneurons of the rat isolated spinal cord.
Eur J Neurosci
; 7(6): 1229-34, 1995 Jun 01.
Article
in En
| MEDLINE
| ID: mdl-7582096
ABSTRACT
Intracellular recording was used to study the effect of cyclothiazide, a selective blocker of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptor desensitization, on lumbar motoneurons of the rat isolated spinal cord. Cyclothiazide (25 microM) enhanced the responses to AMPA in a tetrodotoxin-insensitive fashion, without affecting those produced by N-methyl-D-aspartate or gamma-aminobutyric acid. Excitatory postsynaptic potentials (EPSPs) evoked by dorsal root stimulation were strongly potentiated in amplitude while paired-pulse depression (produced by applying pairs of pulses at 2 s interval) of the EPSP was decreased. In the presence of cyclothiazide the frequency of spontaneous synaptic events was greatly increased and network-driven bursting activity developed with eventual loss of electrical excitability. The present results suggest that pharmacological block of AMPA receptor desensitization led to strong excitation of motoneurons and indicate a physiological role of desensitization in protecting these nerve cells from overactivity.
Search on Google
Database:
MEDLINE
Main subject:
Spinal Cord
/
Receptors, AMPA
/
Synaptic Transmission
/
Motor Neurons
Limits:
Animals
Language:
En
Year:
1995
Type:
Article