ISSN:
0148-7280
Keywords:
oocyte
;
demecolcine
;
Colcemid
;
meiosis
;
germinal vesicle migration
;
microelectrode intracellular recording
;
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
Notes:
Demecolcine (Colcemid; DE), a colchicine derivative, augmented meiosis reinitiation by progesterone in the follicle-enclosed oocyte of the frog, Rana pipiens. Whereas DE treatment alone had a minor stimulatory effect on germinal vesicle dissolution (GVD), this treatment elicited significant germinal vesicle movement (GVM) as evidenced by translocation of the GV to the oocyte surface. The effects of DE on GVM and progesterone-induced GVD were also elicited in oocytes lacking follicle cells or other follicle wall components (type IV follicles), indicating that DE has a direct action on the oocyte itself. DE alone did not alter oocyte membrane voltage (Vm), resistance (Rm), or current (Im) and did not interfere with the changes in these parameters usually elicited by progesterone. After 5 hr incubation of follicle-enclosed oocytes with either DE or progesterone, or combinations of both, the GV could be moved to the animal pole surface with less centrifugal force compared to control follicles. This result suggests that a decrease in ooplasmic viscoelasticity is induced by progesterone, which is mimicked by DE before GVM or GVD normally begins. The results presented here support the idea that DE-sensitive oocyte components such as microtubules are involved in the process of steroid-induced meiosis. These findings provide a physiological basis for future studies of cytoskeletal involvement in the events of meiosis.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrd.1120140103
Permalink
