Effect of basal lamina of ovarian follicle on T- and L-type Ca2+ currents in differentiated granulosa cells
1 Department of Basic Medical Sciences, School of Veterinary Medicine, and 2 Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907 Patch clamp experiments were conducted to study the effects of basal lamina (basement membrane) of chicken ovarian follicle on membrane C...
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Veröffentlicht in: | American journal of physiology: endocrinology and metabolism 2002-01, Vol.282 (1), p.E184 |
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Sprache: | eng |
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Zusammenfassung: | 1 Department of Basic Medical Sciences, School of Veterinary
Medicine, and 2 Department of Biological Sciences, Purdue
University, West Lafayette, Indiana 47907
Patch clamp experiments were conducted to study the effects of
basal lamina (basement membrane) of chicken ovarian follicle on
membrane Ca 2+ currents in differentiated chicken granulosa
cells in a homologous system. The whole cell patch clamp technique was
used to simultaneously monitor membrane capacitance (an indirect
measure of total cell surface area) and currents flowing through
voltage-dependent Ca 2+ channels (using Ba 2+ as
the charge carrier). Membrane capacitance was smaller in cells incubated on intact basal lamina than in control cells (incubated on
tissue culture-treated plastic substratum). Granulosa cells expressed
both T- and L-type Ca 2+ currents, and the amplitudes of the
currents in cells incubated on intact basal lamina were significantly
lower than those of control cells. Also, granulosa cells incubated on
intact basal lamina were found to have significantly lower T- or L-type
Ca 2+ current densities than control cells. Intact basal
lamina that had been stored for 12 mo produced effects on T- and L-type
Ca 2+ currents similar to those caused by freshly isolated
basal lamina. The basal lamina was solubilized completely in one step
and used to coat glass coverslips (uncoated glass coverslips served as controls). Granulosa cells incubated on coverslips precoated with solubilized basal lamina assumed spherical shape similar to those incubated on intact basal lamina. Similar to the observations made for
intact basal lamina, the solubilized basal lamina suppressed T- and
L-type Ca 2+ currents in the differentiated granulosa cells.
Moreover, fibronectin, laminin, and type IV collagen, obtained from
commercial sources, attenuated T- and L-type Ca 2+ currents
in the differentiated granulosa cells. This interplay between basal
lamina and Ca 2+ currents may be one mechanism that
subserves the effects of the matrix material on metabolic functions of
granulosa cells.
basement membrane; extracellular matrix; calcium current; calcium
channel; patch clamp; ovary; chicken; fibronectin; laminin; type IV
collagen |
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ISSN: | 0193-1849 1522-1555 |
DOI: | 10.1152/ajpendo.2002.282.1.E184 |