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Titolo:
Cyclopiazonic acid, an inhibitor of calcium-dependent ATPases, induces exit from metaphase I arrest in growing pig oocytes
Autore:
Petr, J; Rozinek, J; Vanourkova, Z; Jilek, F;
Indirizzi:
Res Inst Anim Prod, Dept Reprod Biol & Mol Genet, Prague 10401 10, Uhrineves, Czech Republic Res Inst Anim Prod Prague Uhrineves Czech Republic 10401 10 zech Republic Czech Univ Agr, Dept Vet Sci, Prague 16521 6, Czech Republic Czech Univ Agr Prague Czech Republic 16521 6 gue 16521 6, Czech Republic
Titolo Testata:
REPRODUCTION FERTILITY AND DEVELOPMENT
fascicolo: 4-5, volume: 11, anno: 1999,
pagine: 235 - 246
SICI:
1031-3613(1999)11:4-5<235:CAAIOC>2.0.ZU;2-3
Fonte:
ISI
Lingua:
ENG
Soggetto:
INOSITOL 1,4,5-TRISPHOSPHATE RECEPTOR; INTRACELLULAR CA2+ STORES; CELL-CYCLE PROGRESSION; MOUSE OOCYTES; PORCINE OOCYTES; CALMODULIN ANTAGONIST; MEIOTIC COMPETENCE; CYTOPLASMIC MATURATION; SARCOPLASMIC-RETICULUM; EGG ACTIVATION;
Keywords:
meiotic maturation; meiotic competence; calcium deposits;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
87
Recensione:
Indirizzi per estratti:
Indirizzo: Petr, J Res Inst Anim Prod, Dept Reprod Biol & Mol Genet, Prague 10401 10,Uhrineves, Czech Republic Res Inst Anim Prod Prague Uhrineves Czech Republic 10401 10 ublic
Citazione:
J. Petr et al., "Cyclopiazonic acid, an inhibitor of calcium-dependent ATPases, induces exit from metaphase I arrest in growing pig oocytes", REPROD FERT, 11(4-5), 1999, pp. 235-246

Abstract

Calcium plays an important role in the regulation of meiotic maturation inmammalian oocytes. In the present study, mycotoxin cyclopiazonic acid (CPA), an inhibitor of calcium-dependent ATPases, was used to mobilize intracellular calcium deposits in growing pig oocytes, which had not attained Full meiotic competence and in which maturation is thus spontaneously blocked atthe metaphase I stage. CPA treatment significantly increased the ratio of growing oocytes that are able to overcome the spontaneously occurring metaphase I block to complete their maturation at the metaphase II stage. CPA treatment of a least 2 hours' duration is necessary to overcome the metaphaseI block in growing oocytes. A similar effect upon release from the spontaneous meiotic block at the metaphase I stage was observed after treatment ofgrowing pig oocytes with thapsigargin, another inhibitor of endogenous calcium-dependent ATPases. Numerous calcium deposits in vacuoles, the mitochondria and on the surface of yolk granules in growing pig oocytes were observed. CPA treatment is able to mobilize calcium from the mitochondria, but deposits in vacuoles and deposits on the surface of yolk granules seem to remain intact after CPA treatment. A microinjection of heparin, which is knownto bind with the inositol trisphosphate receptors, significantly decreasedthe ratio of CPA-treated growing oocytes overcoming the block at the metaphase I stage. This indicates that CPA might mobilize calcium in growing pigoocytes through inositol trisphosphate receptors. On the other hand a microinjection of procaine or a microinjection of ruthenium red both inhibitorsof ryanodine receptors, did not prevent the overcoming of the metaphase I block, induced by CPA treatment. The calcium channel blocker, verapamil, significantly reduces the proportion of CPA-treated growing oocytes that overcome the metaphase I block. This indicates that the influx of calcium from extracellular sources is necessary to overcome the metaphase I block. The calmodulin inhibitors ophiobolin A and W7 also reduce the proportion of CPA-treated growing oocytes overcoming the metaphase I block.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/11/20 alle ore 09:59:42