Spider toxins selectively block calcium currents in Drosophila.
Toxins from spider venom, originally purified for their ability to block synaptic transmission in Drosophila, are potent and specific blockers of Ca2+ currents measured in cultured embryonic Drosophila neurons using the whole-cell, patch-clamp technique. Differential actions of toxins from two species of spiders indicate that different types of Drosophila neuronal Ca2+ currents can be pharmacologically distinguished. Hololena toxin preferentially blocks a non-inactivating component of the current, whereas Plectreurys toxin blocks both inactivating and non-inactivating components. These results suggest that block of a non-inactivating Ca2+ current is sufficient to block neurotransmitter release at Drosophila neuromuscular junction.
Leung
H T
HT
Department of Biological Sciences, University of Southern California, Los Angeles 90089.
Branton
W D
WD
Phillips
H S
HS
Jan
L
L
Byerly
L
L
D000818:Animals; D001180:Arthropod Venoms / Q000494:pharmacology*; D002118:Calcium / Q000502:physiology*; D005591:Chemical Fractionation; D004330:Drosophila / Q000196:embryology / Q000502:physiology*; D004351:Drug Resistance; D004553:Electric Conductivity; D004594:Electrophysiology; D004625:Embryo, Nonmammalian / Q000502:physiology; D009994:Osmolar Concentration; D011188:Potassium / Q000502:physiology; D012964:Sodium / Q000502:physiology; D013111:Spider Venoms / Q000494:pharmacology*; D014118:Toxins, Biological / Q000494:pharmacology*
D001180:Arthropod Venoms; D013111:Spider Venoms; D014118:Toxins, Biological; D012964:Sodium; D011188:Potassium; D002118:Calcium