Scorpion venom inhibits carbamylcholine-induced 86rubidium efflux from rat parotid acini.
The muscarinic agonist carbamylcholine stimulated 5-fold 86Rb efflux from preloaded rat parotid acini. Apamin was without effect on this carbamylcholine-induced 86Rb efflux. By contrast, the venom from Leiurus quinquestriatus (a scorpion from Israel) inhibited non-competitively this efflux while being without effect on the carbamylcholine-stimulated 45Ca efflux and amylase release. This heat-resistant inhibitory effect of the venom was destroyed by boiling in the presence of dithiothreitol. These results suggest that the venom from L. quinquestriatus contains a toxin capable to block apamin-insensitive calcium-activated potassium channels in rat parotid acini.
D000818:Animals; D002217:Carbachol / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D005260:Female; D066298:In Vitro Techniques; D007700:Kinetics; D010306:Parotid Gland / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012413:Rubidium / Q000378:metabolism*; D012604:Scorpion Venoms / Q000494:pharmacology*
D012604:Scorpion Venoms; D002217:Carbachol; D012413:Rubidium