[Low conductivity calcium channels in the plasmatic membrane of macrophages: activation with inositol 1,4,5-triphosphate].
Using patch-clamp technique we have shown that the plasma membrane of mouse macrophages contains calcium channels that are activated by inositol (1, 4, 5)-trisphosphate (IP3) and blocked by heparine. Their conductivity properties strongly differentiate them from IP3-activated channels of endoplasmic reticulum, but make it possible to include them to the ICRAC family. By the other hand, properties of the IP3 receptor (IP3R) of our channels are similar to those of endoplasmic IP3R. Basing on these data we suggest that IP3R could be located out of the plasma membrane, and by some conformational changes transduces the signal to the high selective Ca2+ channel in the plasma membrane. This model well conforms with the known in the literature "coupling model" of calcium signalling [1].
Institute of Cytology of the Russian Acad. Sci., St. Petersburg, Russia.
S B
SB
Semenova
K I
KI
Kiselev
G N
GN
Mozhaeva
D000818:Animals; D015220:Calcium Channels / Q000502:physiology*; D002462:Cell Membrane / Q000502:physiology; D002478:Cells, Cultured; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology / Q000502:physiology*; D017737:Macrophages, Peritoneal / Q000502:physiology* / Q000648:ultrastructure; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D018408:Patch-Clamp Techniques
D015220:Calcium Channels; D015544:Inositol 1,4,5-Trisphosphate
Kal'tsievye kanaly nizkoĭ provodimosti v plazmaticheskoĭ membrane makrofagov: aktivatsiia inozitol (1,4,5)-trifosfatom.