[Latrotoxin channels. Permeability for divalent cations].
The dependence of Ca2+ transport in synaptosomes along the channels formed by alpha-latrotoxin on [Ca2+]in and the feasibility of transport along these channels of other bivalent cations were studied. It was found that the concentration dependence of Ca2+ influx is nonlinear and is described by the Michaelis-Menten kinetics (Km = 1.07 +/- 0.19 mM). Mg2+, Ba2+, Sr2+, Mn2+ and Co2+ competitively inhibited the Ca2+ influx via latrotoxin channels. Studies with the use of the fluorescent Ca2+ probes, Quin-2 and Fura-2, revealed that these cations can also penetrate inside synaptosomes via latrotoxin channels. The bivalent cation influx via latrotoxin channels caused a decrease of the membrane potential of synaptosomes. The similarity of properties of latrotoxin and endogenous Ca2+ channels is discussed.
Lishko
V K
VK
Saĭchenko
E A
EA
Storchak
L G
LG
Gimmerl'reĭkh
N G
NG
D000634:Aminoquinolines; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism*; D002413:Cations, Divalent / Q000378:metabolism; D005456:Fluorescent Dyes; D016257:Fura-2; D007473:Ion Channels / Q000378:metabolism*; D007700:Kinetics; D010539:Permeability; D013111:Spider Venoms / Q000378:metabolism*; D013574:Synaptosomes / Q000378:metabolism
D000634:Aminoquinolines; D002413:Cations, Divalent; D005456:Fluorescent Dyes; D007473:Ion Channels; D013111:Spider Venoms; C020763:alpha-latrotoxin; C035739:Quin2; D002118:Calcium; D016257:Fura-2
Latrotoksinovye kanaly. Pronitsaemost' dlia dvukhvalentnykh kationov.