Dendrotoxin blocks a class of potassium channels that are opened by inhibitory presynaptic modulators in rat cortical synaptosomes and slices.
1. Rat cortical synaptosomes were prelabeled with radioactive acetylcholine and the release induced by veratridine was determined in the absence and presence of the inhibitory presynaptic modulators, 2-chloroadenosine, carbamylcholine, clonidine, and morphine. All four agents inhibited the evoked release of acetylcholine and this inhibition was reversed by dendrotoxin. 2. Using perfused cortical slices and an extracellular K-sensitive electrode, all modulators again increased K efflux that was blocked by dendrotoxin. In contrast, glybenclamide and tetraethylammonium did not block the modulator-induced efflux.
Zoltay
G
G
Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06510.
Cooper
J R
JR
D015762:2-Chloroadenosine / Q000494:pharmacology; D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D002540:Cerebral Cortex / Q000187:drug effects*; D003000:Clonidine / Q000494:pharmacology; D004546:Elapid Venoms / Q000494:pharmacology*; D005905:Glyburide / Q000494:pharmacology; D015640:Ion Channel Gating / Q000187:drug effects*; D009020:Morphine / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013574:Synaptosomes / Q000187:drug effects*; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000494:pharmacology; D014701:Veratridine / Q000494:pharmacology
D004546:Elapid Venoms; D015221:Potassium Channels; D013757:Tetraethylammonium Compounds; D015762:2-Chloroadenosine; D019789:Tetraethylammonium; D014701:Veratridine; C020273:dendrotoxin; D009020:Morphine; D002217:Carbachol; D003000:Clonidine; D000109:Acetylcholine; D005905:Glyburide