A functional study on L-type calcium channels in granulosa cells of small follicles in laying and forced molt hens

To investigate Ca2+ dynamics in earlier phases of follicular development we compared the resting [Ca2+](i) and tested the functional responses to agonist/antagonist of L-type voltage-operated calcium channels (VOCCs) in small follicles GCs from hens during oviposition (O-GCs) and forced molt (M-GCs), using the microspectrofluorimetric [Ca2+](i) imaging. O-GCs were obtained from prehierarchical follicles (F-6-F-5-F-4 < 8 mm). In basal and agonist/antagonist stimulated M-GCs we did not observe a change in the [Ca2+](i) under any of condition in all cells analyzed. Based on basal measurements we can distinguish three different patterns reflecting cells variability within O-GCs group: (a) 39% cells showed small oscillations and [Ca2+](i) was 108 +/- 11 nM; (b) 36% cells displayed yet small oscillations and [Ca2+](i) was 167 +/- 14 nM; (c) 25% were cells with repetitive irregular oscillations that peaked until 2 fold basal value and [Ca2+](i) very variable, was 248 +/- 41 nM. In O-GCs L-type VOCCs stimuli displayed different effects on [Ca2+](i) for both treatment in three basal patterns.