The effect of toxin I, a K+ channel inhibitor, on [3H]noradrenaline release from rat cerebral cortex.
Toxin I, a K+ channel blocker found in the venom of the black mamba snake with close sequence homology to the dendrotoxins, produced a concentration-related enhancement of both spontaneous and electrically evoked [3H]noradrenaline ([3H]NA) release from slices of rat cerebral cortex. The effect of toxin I on spontaneous [3H]NA release was blocked by tetrodotoxin and reduced in the presence of either CPP ((+-)-3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid) or CNQX (6-cyano-7-nitroquinoxaline-2,3-dione) and was abolished in the presence of both antagonists. The results suggest that the enhancement of spontaneous [3H]NA release produced by toxin I may be mediated via the release of glutamate acting on both NMDA (N-methyl-D-aspartate) and non-NMDA receptors.
Ennis
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Wyeth Research (UK) Ltd., Taplow, Berks, UK.
Minchin
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MC
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D000818:Animals; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D004546:Elapid Venoms / Q000494:pharmacology*; D004558:Electric Stimulation; D066298:In Vitro Techniques; D008297:Male; D009498:Neurotoxins / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D009638:Norepinephrine / Q000378:metabolism*; D015221:Potassium Channels / Q000187:drug effects*; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017470:Receptors, Glutamate / Q000187:drug effects; D013779:Tetrodotoxin / Q000494:pharmacology
D004546:Elapid Venoms; D009498:Neurotoxins; D015221:Potassium Channels; D011810:Quinoxalines; D017470:Receptors, Glutamate; D013779:Tetrodotoxin; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D009638:Norepinephrine