Effect of Diamphidia toxin, a Bushman arrow poison, on ionic permeability in nucleated cells.
The effect of Diamphidia toxin, isolated from pupae of Diamphidia nigro-ornata, was tested on two different cell lines (GH4C1 cells and HL-60 cells) and on human lymphocytes. The toxin raised intracellular Ca2+ concentration, as assessed with quin 2, in a dose-related manner in all three cell types. The effect was abolished when extracellular Ca2+ was chelated by EGTA. Low concentrations of the toxin evoked a delayed as well as a smaller response. The response time was also temperature-dependent, with a Q10 of about 2. Low, but effective concentrations of the toxin did not affect cell membrane integrity, as tested with Trypan blue, and induced a seemingly physiological release of prolactin from the GH4C1 cells. Diamphidia toxin's effect on the membrane permeability of GH4C1 cells was further investigated with patch-clamp techniques. The toxin appeared to increase the conductance for all small ions without affecting the normal ionic channels present in these cells. We conclude that Diamphidia toxin has a general effect on the plasma membrane of different cell types and thereby increases, probably non-specifically, the permeability for small ions.
Jacobsen
T F
TF
Institute of Physiology, University of Oslo, Norway.
Sand
O
O
Bjøro
T
T
Karlsen
H E
HE
Iversen
J G
JG
D000645:Ammonium Sulfate / Q000494:pharmacology; D000818:Animals; D001180:Arthropod Venoms / Q000633:toxicity*; D015220:Calcium Channels / Q000187:drug effects; D002460:Cell Line; D002463:Cell Membrane Permeability / Q000187:drug effects*; D002478:Cells, Cultured; D008564:Membrane Potentials / Q000187:drug effects; D011388:Prolactin / Q000378:metabolism; D051381:Rats; D013696:Temperature
D001180:Arthropod Venoms; D015220:Calcium Channels; C044247:Diamphidia toxin; D011388:Prolactin; D000645:Ammonium Sulfate