Activation of in vitro matured pig oocytes using activators of inositol triphosphate or ryanodine receptors.
In our study, we observed the activation of in vitro matured pig oocytes and their subsequent parthenogenetic cleavage after stimulation of ryanodine receptors (RyR) using ryanodine (Ry), caffeine or cyclic adenosine diphosphate ribose (cADPri) or after stimulation of inositol triphosphate receptors (IP(3)R) using D-myo-inositol 1,4,5-triphosphate (IP(3)). Heparin, a potent blocker of IP(3)R, prevented the activation of porcine oocytes using IP(3), but blockers of RyR (ruthenium red or procaine) prevented activation after stimulation by RyR and stimulation by IP(3)R using IP(3). The drugs were injected into oocytes matured to the stage of metaphase II and activation was determined by assessment of pronuclear formation. The activity of H1 kinase was determined and our results demonstrated a significant drop in H1 activity in the activated oocytes. The cleavage of parthenogenetic embryos progresses to more advanced stages after stimulation by IP(3)R than after stimulation by RyR. Our results could indicate that, in pig oocytes, the calcium released from IP(3)-sensitive stores triggers the calcium release from ryanodine-sensitive intracellular stores, which is necessary for oocyte activation. The calmodulin inhibitors ophiobolin A and W7 reduce the activation of oocytes induced by stimulation of RyR or IP(3)R.
Petr
J
J
Department of Reproductive Biology, Research Institute of Animal Production, Prague 10, Uhríneves 104 01, Czech Republic. petr@vuzv.cz
Urbánková
D
D
Tománek
M
M
Rozinek
J
J
Jílek
F
F
D000246:Adenosine Diphosphate Ribose / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000187:drug effects; D002147:Calmodulin / Q000037:antagonists & inhibitors / Q000502:physiology; D002467:Cell Nucleus / Q000648:ultrastructure; D036563:Cyclic ADP-Ribose; D005260:Female; D006493:Heparin / Q000494:pharmacology; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism* / Q000494:pharmacology; D053496:Inositol 1,4,5-Trisphosphate Receptors; D008677:Metaphase; D008845:Microinjections; D009865:Oocytes / Q000187:drug effects* / Q000502:physiology* / Q000648:ultrastructure; D010312:Parthenogenesis; D018160:Receptors, Cytoplasmic and Nuclear / Q000187:drug effects; D012433:Ryanodine / Q000494:pharmacology; D019837:Ryanodine Receptor Calcium Release Channel / Q000187:drug effects* / Q000502:physiology; D013552:Swine / Q000502:physiology*
D015220:Calcium Channels; D002147:Calmodulin; D053496:Inositol 1,4,5-Trisphosphate Receptors; D018160:Receptors, Cytoplasmic and Nuclear; D019837:Ryanodine Receptor Calcium Release Channel; D036563:Cyclic ADP-Ribose; D012433:Ryanodine; D000246:Adenosine Diphosphate Ribose; D002110:Caffeine; D015544:Inositol 1,4,5-Trisphosphate; D006493:Heparin; D002118:Calcium