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Cell Adhesion and Fusion Induced by Insemination in Zona‐Free Hamster Eggs: Electrophysiological Monitoring of the Fusion Process
Author(s) -
URABE MASASHI,
KAWAKAMI TADATAKA,
IGUSA YUKIO,
MIYAZAKI SHUNICHI
Publication year - 1985
Publication title -
development, growth and differentiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.864
H-Index - 66
eISSN - 1440-169X
pISSN - 0012-1592
DOI - 10.1111/j.1440-169x.1985.00041.x
Subject(s) - cell fusion , fusion , electrophysiology , process (computing) , hamster , insemination , microbiology and biotechnology , lipid bilayer fusion , chemistry , biophysics , cell , biology , andrology , neuroscience , medicine , computer science , biochemistry , sperm , philosophy , linguistics , operating system
Cell adhesion and fusion were found to occur in zona‐free hamster eggs placed in contact and then inseminated. A cytoplasmic fusion occurred in 7% of paired eggs mainly between 10 and 50 min after insemination. All other eggs that failed to fuse adhered tightly to one another within about 1 hr. Electrophysiological monitoring of the fusion process revealed that an electrical coupling (EC) suddenly appears between apposed eggs and completed within 2–15 min as the first step of cell fusion. Periodic hyperpolarizing responses (HRs), which have been found previously in fertilized hamster eggs to reflect a periodic increase in cytoplasmic Ca 2+ ions, become gradually synchronized and completely coincide in paired eggs 10–30 min after the establishment of EC. Thus the paired eggs become an electrically single cell as the second step. Then the boundary between the eggs breaks down, resulting in formation of a single, spherical egg in several minutes. On the other hand, most of adhered eggs showed neither EC nor synchronization of HRs. Some adhered eggs showed only a low efficiency EC.