Reconstitution of neurotransmission by determining communication between differentiated PC12 pheochromocytoma and HEL 92.1.7 erythroleukemia cells.
Neurotransmitter release was monitored using fura-2-loaded HEL 92.1.7 cells dispersed among differentiated PC12 cells (loaded with another Ca2+ indicator fluo-3) and immobilised using transparent polycarbonate membrane filters with uniform pore size. Depolarisation with K+ caused a rapid rise in Ca2+ concentration in the PC12 cells, followed by a delayed secondary Ca2+ response in simultaneously monitored nearby HEL cells. There was a lag period of about 20 s between the responses of the two cell types. Voltage-gated Ca2+ channels in PC12 cells were inhibited by the P/Q-type (omega-conotoxin MVIIC, omega-agatoxin IVA), N-type (omega-conotoxin GVIA) and L-type channel blockers (nifedipine) as determined using fura-2 or whole-cell patch-clamp recordings. The communication between the cell types on the other hand was sensitive to P/Q- and N-type but not to L-type channel blockers. This suggests that, as in neurons, P/Q- and N-type Ca2+ channels mediate the release of neurotransmitters acting on HEL cells. Theoretically, the procedure employed should be sensitive enough to detect single exocytotic events. Our results demonstrate that a random distribution between effector and target cells is sufficient to allow communication between cells in a manner similar to extrasynaptic transmission.
Shariatmadari
R
R
Department of Physiology, Division of Cell Physiology, Uppsala University, BMC, PO Box 572, S-75123 Uppsala, Sweden.
Lund
P E
PE
Krijukova
E
E
Sperber
G O
GO
Kukkonen
J P
JP
Akerman
K E
KE
D000818:Animals; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000502:physiology; D002450:Cell Communication / Q000502:physiology; D002454:Cell Differentiation; D004594:Electrophysiology; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D004915:Leukemia, Erythroblastic, Acute / Q000473:pathology / Q000503:physiopathology*; D020932:Nerve Growth Factor / Q000494:pharmacology; D018377:Neurotransmitter Agents / Q000378:metabolism / Q000502:physiology; D009994:Osmolar Concentration; D016716:PC12 Cells / Q000473:pathology / Q000502:physiology*; D051381:Rats; D009435:Synaptic Transmission / Q000502:physiology*; D014407:Tumor Cells, Cultured / Q000187:drug effects
D015220:Calcium Channels; D018377:Neurotransmitter Agents; D020932:Nerve Growth Factor; D002118:Calcium