Miniature postsynaptic currents depend on Ca2+ released from internal stores via PLC/IP3 pathway.
Miniature postsynaptic currents (mPSCs) were examined on autaptic innervation of single rat retinal ganglion cells in low density cultures. Removal of Ca2+ from bath solution or blocking of Ca2+ channels by Cd2+ had no detectable effect on mPSC frequency or amplitude. Thapsigargin, an agent for mobilization of Ca2+ from internal stores, increased mPSC frequency 3-5-fold in control, Ca2+-free or Cd2+-containing solutions. The inositol 1,4,5-triphosphate (IP3) receptor antago- nist, heparin; the phospholipase C (PLC) inhibitor, U73122; and caffeine abolished mPSC or decreased mPSCs frequency. Calcium imaging showed that cytosolic Ca2+ was increased by thapsigargin and decreased by caffeine. These data demonstrate that internal store-released Ca2+ regulated by the PLC/IP3/IP3-receptor pathway has critical contribution to generation and control of miniature release in retinal ganglion cells.
Han
M H
MH
Department of Ophthalmology and Visual Science, Yale University School of Medicine, PO Box 208061, 330 Cedar Street, New Haven, CT 06520, USA.
Kawasaki
A
A
Wei
J Y
JY
Barnstable
C J
CJ
D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000502:physiology*; D015220:Calcium Channels / Q000378:metabolism; D020013:Calcium Signaling / Q000502:physiology*; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004963:Estrenes / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology*; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism / Q000502:physiology*; D053496:Inositol 1,4,5-Trisphosphate Receptors; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D011760:Pyrrolidinones / Q000494:pharmacology; D051381:Rats; D020318:Rats, Long-Evans; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D012165:Retinal Ganglion Cells / Q000187:drug effects / Q000378:metabolism*; D019284:Thapsigargin / Q000494:pharmacology; D010738:Type C Phospholipases / Q000378:metabolism*
D015220:Calcium Channels; D004791:Enzyme Inhibitors; D004963:Estrenes; D053496:Inositol 1,4,5-Trisphosphate Receptors; D010726:Phosphodiesterase Inhibitors; D011760:Pyrrolidinones; D018160:Receptors, Cytoplasmic and Nuclear; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D002110:Caffeine; D019284:Thapsigargin; D015544:Inositol 1,4,5-Trisphosphate; D010738:Type C Phospholipases; D002118:Calcium