Regional differences in nerve terminal Na+ channel subtype expression and Na+ channel-dependent glutamate and GABA release in rat central nervous system
We tested the hypothesis that expression of presynaptic voltage-gated Na + channel (Na v ) subtypes coupled to neurotransmitter release differs between transmitter types and CNS regions in a nerve terminal-specific manner. Na v coupling to transmitter release was determined by measuring the sensitiv...
Saved in:
Published in | Journal of neurochemistry Vol. 113; no. 6; pp. 1611 - 1620 |
---|---|
Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
29.03.2010
|
Online Access | Get full text |
Cover
Loading…
Summary: | We tested the hypothesis that expression of presynaptic voltage-gated Na
+
channel (Na
v
) subtypes coupled to neurotransmitter release differs between transmitter types and CNS regions in a nerve terminal-specific manner. Na
v
coupling to transmitter release was determined by measuring the sensitivity of 4-aminopyridine (4AP)-evoked [
3
H]glutamate and [
14
C]GABA release to the specific Na
v
blocker tetrodotoxin (TTX) for nerve terminals isolated from rat cerebral cortex, hippocampus, striatum and spinal cord. Expression of various Na
v
subtypes was measured by immunoblotting using subtype-specific antibodies. Potencies of TTX for inhibition of glutamate and GABA release were similar between CNS regions. However, the efficacies of TTX for inhibition of 4AP-evoked glutamate release were greater than for inhibition of GABA release in all regions except spinal cord. The relative nerve terminal expression of total Na
v
subtypes as well as of specific subtypes varied considerably between CNS regions. The region-specific potencies of TTX for inhibition of 4AP-evoked glutamate release correlated with greater relative expression of total nerve terminal Na
v
and Na
v
1.2. Nerve terminal-specific differences in the expression of specific Na
v
subtypes contribute to transmitter-specific and regional differences in pharmacological sensitivities of transmitter release. |
---|---|
ISSN: | 0022-3042 1471-4159 |
DOI: | 10.1111/j.1471-4159.2010.06722.x |