Effect of basal lamina of ovarian follicle on T- and L-type Ca²⁺currents in differentiated granulosa cells

Abstract

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.

Cocaine- and Amphetamine-Regulated Transcript Regulation of Follicle-Stimulating Hormone Signal Transduction in Bovine Granulosa Cells

“…This suggests that in addition to L-type Ca 2ϩ channels, CART may also regulate activity of other Ca 2ϩ channels. Expression of L-and T-type Ca 2ϩ channels in GCs has been reported previously (65)(66)(67)(68). There is also evidence of G o/i--dependent inhibition of L-, N-, and P/Q-type Ca 2ϩ channels in rat lateral hypothalamic neurons (69).…”

Expression and localization of the progesterone receptor in mouse and human reproductive organs

“…The increased non-nuclear PR localization in granulosa cells of preovulatory follicles could therefore represent membrane-bound PR forms that act through Ca 2C signaling and possibly in coordination with Ca 2C channels and Ca 2C currents (Asem et al 2002). In rat ovaries, P was suggested to inhibit granulosa cell apoptosis through the binding and activation of a 60 kDa membrane protein that functions as a low-affinity, high-capacity receptor for P (Peluso et al 2001, Peluso 2004.…”

Feed Intake Alters Immune Cell Functions and Ovarian Infiltration in Broiler Hens: Implications for Reproductive Performance1

“…This was done to avoid F1 follicle terminal-differentiation-associated-cellular-senescence that can interfere with treatment responses [27]. In each co-culture experiment, granulosa cells were collected from two actively laying, 33-35 wk old R hens and monocytes and heterophils were collected from another two R or AL hens.…”