Intracellular calcium mobilization following prostaglandin receptor activation in human ciliary muscle cells.

PURPOSE: To investigate the presence of specific prostaglandin receptors in primary cultures of human ciliary muscle cells by measuring agonist-stimulated intracellular calcium mobilization.

METHODS

The ciliary muscle cells, cultured from postmortem human ciliary muscle explants, were first characterized by anti-desmin and anti-smooth muscle alpha-actin antibodies. Increase in intracellular calcium concentrations, in fura 2-AM loaded human ciliary muscle cells stimulated by prostaglandin receptor agonists, were determined with a digital fluorescence imaging system.

RESULTS

The resting intracellular calcium concentration in the fura 2-AM loaded cells was 60.0 +/- 6.0 nM. The threshold concentration of PG receptor agonists needed to increase the concentration of intracellular calcium was 10(-8) M. The stimulation of these cells by PGF2 alpha, 17-phenyl trinor PGE2, and U46619, the FP, EP1, and TP receptor agonists, resulted in the dose-dependent increase of intracellular calcium.

CONCLUSION

The results of the present study suggest that EP1, FP, and TP receptors are present in human ciliary muscle cells.