IHEM   20887
INSTITUTO DE HISTOLOGIA Y EMBRIOLOGIA DE MENDOZA DR. MARIO H. BURGOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
2-AMINOETHOXYDIPHENYL BORATE (2-APB) TRIGGERS CORTICAL REACTION IN MOUSE OOCYTES
Autor/es:
CAPPA, ANDREA I.; DE PAOLA, M. MATILDE; MICHAUT, MARCELA A.
Lugar:
Tucumán
Reunión:
Congreso; 3ª Reunión Conjunta de Sociedades de Biología de la República Argentina; 2015
Institución organizadora:
Sociedad de Biología de Tucumán
Resumen:
Cortical reaction is a calciumdependentexocytosis that plays a key role in blocking polyspermy. It consistsin the fusion of cortical granules with plasma membrane during oocyteactivation, which is triggered by fertilization or parthenogenetic activation.2-APB is an IP3 receptor´s inhibitor that prevents secretion in some exocytoticmodels;nevertheless,it induces a calcium pulse and activates oocytes parthenogenetically. Based onthis, we hypothesized that 2-APB is a new parthenogeneticinductorof corticalreaction.To evaluate the role of 2-APB in this secretory process, we used amethod developed in our laboratory that allows us to analyze cortical reactionin real time. Matured oocytes obtained fromhormonally stimulated CF-1 femalesmicewere collected from ampulla and incubated with or without 2-APB inMEM/HEPES medium in presence of Lensculinaris agglutinin conjugated with FITC(LCA-FITC). LCA-FITC has affinityfor the content of cortical granules and labels fluorescently its secretion.Images were taken every 30 s during 20 min using an inverted microscopewith LEDilluminationand a high resolution camera. Then, cells were fixed and notsecreted cortical granuleswere labeled with LCA-Rhodamine for quantification.The results showedthat cortical reactionoccurred inthe first5-8minonly in thoseoocytesincubated in the presenceof200 µM 2-APB. Cortical granulesquantification using LCA-Rhodamineshowed a significant decreasein the densityofthe remaining cortical granules. In conclusion,2-APB triggers cortical granules exocytosis duringcortical reaction in mouse oocytes.