The postnatal development of the oscillatory potentials of the electroretinogram IV. Mesopic characteristics

Abstract

The postnatal development of the oscillatory potentials (OP) of the rat's electroretinogram (ERG) was studied during relatively mesopic adaptational conditions. The behaviour of the OPs induced at an interstimulus interval (ISI) of 30 sec entailed photopic qualities at an individual level, but when summated conformed to a scotopic course of postnatal maturation. An ISI of 1 min elicited OPs with individual scotopic characteristics. The total oscillatory activity culminated at 17 days of age at both ISIs, similar to more scotopically induced oscillations. These results show that relatively mesopic states of adaptation do not promote any earlier appearance of the OPs, and that the immature mesopically induced OPs seem to contain both scotopic and photopic qualities reflecting a postnatal change of balance between these components. Furthermore, photopic mechanisms seem to govern the oscillatory activity in the mature rat retina. We suggest that the differences in relation to adaptational conditions between the immature and mature OPs may reflect the postnatal status of the dopamine and its synthetizing enzyme, tyrosine-hydroxylase.

Synaptogenesis and synaptic protein localization in the postnatal development of rod bipolar cell dendrites in mouse retina

“…Around the time of eye opening, P14, we observe that the number of tips with both proteins is 59%, a period when the scotopic ERG b ‐wave is already present in mice (Bakall et al, ). In rats, a small b ‐wave is present around P14, which increases ∼4‐fold by P30 and declines modestly at P40 (el Azazi & Wachtmeister, ). Interestingly, we observe a similar pattern in the number of dendritic tips—tips increase significantly until P30 and decrease modestly, but not significantly, by P82.…”