Calbindin and parvalbumin immunoreactivity in the developing and adult human retina.

We report the expression and pattern of two calcium-binding proteins (CBPs), calbindin (CALB) and parvalbumin (PV), in the fetal (13-25 weeks of gestation), postnatal (5 months) and adult human retina, as studied by immunohistochemistry. Both CBPs appear prenatally in different neurones as well as in the nerve fibre, inner and outer plexiform layers. The cones do not show immunoreactivity for both CBPs up to 25 weeks, the last fetal stage studied; however, they are immunopositive in the postnatal and adult retina. Of the two CBPs, CALB appears first, followed by PV. The immunoreactivity for both CALB and PV in the fetal retina follows a centroperipheral gradient and vitreal to scleral pattern of retinal differentiation. The CALB immunoreactivity shows a gradual increase in intensity with age. A spurt in intensity of PV immunoreactivity in the 24-25 week fetal retina and increased intensity in the 60 year normal adult retina when compared to the light-deprived retina of a 34-year-old staphyloma patient suggests an activity-dependent functional role for PV.