Effects of sodium on PKC translocation; relationship to neurotransmitter release.
Our previous work using Na+ channel activators such tityustoxin (TsTX), indicated that local increases in Na+ modulate glutamate release from synaptosomes. We have now investigated the role of the Ca2+/phospholipid-dependent protein kinase (PKC) in mediating this effect. TsTX and KCl stimulate 'fast' glutamate release to the same extent but TsTX is more effective than KCl in enhancing the 'slow' phase of release. KCl greatly stimulates PKC translocation. However, TsTX inhibits basal and phorbol ester-induced translocation while the Na(+)-ionophore, gramicidin D, has no effect. Taken together, these data suggest TsTX mediated localized Na+ entry inhibits PKC translocation and that this effect may be associated with recruitment of vesicles to the readily releasable pool.
Basudev
H
H
Institute of Psychiatry, Department of Neuroscience, Denmark Hill, London, UK.
Romano-Silva
M A
MA
Brammer
M J
MJ
Campbell
I C
IC
D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D004789:Enzyme Activation; D006096:Gramicidin / Q000494:pharmacology; D008297:Male; D018377:Neurotransmitter Agents / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism; D011189:Potassium Chloride / Q000494:pharmacology; D011493:Protein Kinase C / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D012604:Scorpion Venoms / Q000494:pharmacology; D012964:Sodium / Q000494:pharmacology*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D018377:Neurotransmitter Agents; D012604:Scorpion Venoms; D006096:Gramicidin; C003609:tityustoxin; D005680:gamma-Aminobutyric Acid; D011189:Potassium Chloride; D012964:Sodium; D011493:Protein Kinase C; D000109:Acetylcholine; D002118:Calcium; D009638:Norepinephrine