title: Animal models in micromanipulation.
abstract: Micromanipulation is a useful technique for various studies of reproductive biology. Using this technique, we investigated the role of cAMP in the regulation of oocyte maturation. Anti cAMP serum was microinjected into oocyte cytoplasma. Immature oocytes resumed meiosis after microinjection and this result shows oocyte cAMP to be important for the intrafollicular meiotic arrest of oocyte and its decrease to cause resumption of meiosis. We also determined maturation promotion factor (MPF) activity in the mouse egg. Microinjection of cytoplasma from mature egg induced geminal vesicle break down of immature oocyte in the presence of dbcAMP. In addition, we detected MPF activity in cytoplasma of metaphase II oocyte. Some of the initial events of sperm-induced egg activation are accompanied by hydrolysis of phosphatidyl inositol which generates inositol trisphosphate (IP3). Mouse eggs microinjected with increasing concentration of IP3 revealed concentration dependent increase in conversion of the zona glycoprotein ZP2 to ZP2f. Modification of zona pellucida elicited by microinjection of IP3 are similar to those that occur following fertilisation. We also microinjected some cytoplasma of morula or 2 cell mouse embryo into 1 cell embryo of ICR mouse. After microinjection and culture, most of the embryo that reached 4 cells stage and 2 cell block of ICR mouse embryo was released significantly. These results suggest that some cytoplasmic factor(s) is a requisite for the development of embryo after fertilisation.
authors.affiliation: Department of Obstetrics and Gynaecology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Suzuki
authors.forename: S
authors.initials: S
authors.lastname: Kurasawa
authors.forename: S
authors.initials: S
authors.lastname: Ohmura
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000502:physiology; D000242:Cyclic AMP / Q000502:physiology; D004492:Edetic Acid / Q000494:pharmacology; D005260:Female; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology; D008297:Male; D016200:Maturation-Promoting Factor / Q000502:physiology; D008540:Meiosis / Q000502:physiology; D000090204:Mesothelin; D051379:Mice; D008813:Mice, Inbred ICR; D008846:Micromanipulation; D009866:Oogenesis / Q000502:physiology*; D013084:Sperm-Ovum Interactions / Q000502:physiology; D015044:Zona Pellucida / Q000502:physiology
chemical_list: C000715528:Msln protein, mouse; D015544:Inositol 1,4,5-Trisphosphate; D004492:Edetic Acid; D000242:Cyclic AMP; D016200:Maturation-Promoting Factor; D000090204:Mesothelin