Bui B V, Vingrys A J
Department of Optometry and Vision Sciences, University of Melbourne, Victoria, Australia.
Doc Ophthalmol. 1999;99(2):151-70. doi: 10.1023/a:1002721315955.
We describe the postnatal development of the electroretinogram (ERG) receptoral response in the guinea pig. In addition, the time course and nature of maturation was compared between albino and pigmented strains to consider the role that melanogenesis might have in this process. Electroretinograms were collected on groups of albino and pigmented animals from postnatal day (PD) PD1 to PD60. A-wave amplitudes and implicit times were extracted from filtered data (0-75 Hz). Receptoral components were modelled using the delayed gaussian model of Hood and Birch [1] fitted as an ensemble to the raw data. Guinea pigs show saturated amplitudes (RmP3) that are 50% of adult values at birth, these mature by PD12. Receptoral delay (t(d)) also undergoes some postnatal maturation, while phototransduction gain (log S) is adult-like at birth. Albino animals had significantly (p<0.05) larger RmP3 and log S across all ages. Guinea pigs have significant postnatal development in their receptoral response. Maturation of RmP3 implies a postnatal increase in rod outer segment length. Whereas the adult values of log S implies a mature phototransduction process at birth. We argue that the likely cause for the larger log S of albino eyes is compatible with theories of increased levels of internal light. Whereas the larger RmP3, even after allowing for increased light effectiveness, may reflect a lower ocular resistance in albino eyes due to their lower levels of melanin. Furthermore, decreased RmP3 and log S with age is observed in the pigmented group only and is consistent with increased ocular resistance due to melanin development in this strain.
我们描述了豚鼠视网膜电图（ERG）感受器反应的出生后发育情况。此外，还比较了白化豚鼠和有色豚鼠品系成熟的时间进程和性质，以探讨黑色素生成在此过程中可能发挥的作用。从出生后第1天（PD1）到第60天，对白化豚鼠和有色豚鼠群体进行视网膜电图采集。从滤波后的数据（0 - 75 Hz）中提取A波振幅和隐含时间。感受器成分采用Hood和Birch [1]的延迟高斯模型进行建模，并作为一个整体拟合到原始数据中。豚鼠出生时的饱和振幅（RmP3）为成年值的50%，在PD12时成熟。感受器延迟（t(d)）在出生后也会经历一些成熟过程，而光转导增益（log S）在出生时就类似成年水平。在所有年龄段，白化豚鼠的RmP3和log S均显著更大（p<0.05）。豚鼠的感受器反应在出生后有显著发育。RmP3的成熟意味着出生后视杆外段长度增加。而log S的成年值意味着出生时光转导过程已经成熟。我们认为，白化豚鼠眼睛log S较大的可能原因与内部光水平增加的理论相符。而即使考虑到光效率的提高，较大的RmP3可能反映出白化豚鼠眼睛由于黑色素水平较低而具有较低的眼电阻。此外，仅在有色豚鼠组中观察到RmP3和log S随年龄下降，这与该品系中由于黑色素发育导致的眼电阻增加一致。
