Jain Vrinda, Liang Phillip J M, Raja Sushmitha, Mikhael Meena, Cameron Morven A
School of Medicine, Western Sydney University, Sydney, NSW, Australia.
Mass Spectrometry Facility, Western Sydney University, Sydney, NSW, Australia.
Front Ophthalmol (Lausanne). 2023 May 9;3:1184627. doi: 10.3389/fopht.2023.1184627. eCollection 2023.
The neuromodulator dopamine plays a significant role in light adaptation, eye growth, and modulation of neuronal circuitry in the retina. Dopaminergic amacrine cells in the adult retina release dopamine in response to light stimulation, however, the light-induced activity of these cells in during postnatal development is not known. We assessed the activity of dopaminergic amacrine cells in the retina response to a light pulse in C57BL/6 wild-type animals across various postnatal ages. Expression of tyrosine hydroxylase (TH) in dopaminergic amacrine cells was apparent from postnatal day 3 (P3) and restricted to the dorso-temporal region; by P8 TH+ cells were uniformly distributed across the retina. TH cell density increased until P8 and then markedly decreased by P10 to then remain at this density into adulthood. Light-induced c-fos expression was observed in all light-pulsed retinae, however, no c-fos was ever found to be co-localised with TH prior to P12. At P14, one day after eye opening, 100% of TH cells co-localised with c-fos and this was maintained for all older ages analysed. Dopamine and its primary metabolite DOPAC were measured in the vitreous of animals P8-P30. Both analytes were found in the vitreous at all ages, however, a significant difference in dopamine concentration between dark and light-pulsed animals was only observed at P30. DOPAC concentration was found to be significantly light-induced from P16, and the amplitude of this difference increased over time. Our data suggests that dopaminergic cell activation and light-induced dopamine release in the retina is primarily driven by classical photoreceptors after eye-opening.
神经调质多巴胺在光适应、眼球生长以及视网膜神经回路的调节中发挥着重要作用。成年视网膜中的多巴胺能无长突细胞会对光刺激做出反应而释放多巴胺，然而，这些细胞在出生后发育期间的光诱导活性尚不清楚。我们评估了C57BL/6野生型动物在不同出生后年龄阶段，视网膜中多巴胺能无长突细胞对光脉冲的反应活性。酪氨酸羟化酶（TH）在多巴胺能无长突细胞中的表达从出生后第3天（P3）开始明显可见，且局限于背颞区域；到P8时，TH阳性细胞均匀分布于整个视网膜。TH细胞密度在P8之前持续增加，然后在P10时显著下降，之后一直保持该密度直至成年。在所有接受光脉冲刺激的视网膜中均观察到光诱导的c-fos表达，然而，在P12之前从未发现c-fos与TH共定位。在P14，即睁眼后一天，100%的TH细胞与c-fos共定位，并且在所有分析的较大年龄阶段均保持这种情况。在P8 - P30的动物玻璃体中测量了多巴胺及其主要代谢产物3,4-二羟基苯乙酸（DOPAC）。在所有年龄阶段的玻璃体中均检测到这两种分析物，然而，仅在P30时观察到黑暗和光脉冲刺激动物之间多巴胺浓度存在显著差异。发现从P16开始DOPAC浓度受到显著的光诱导，并且这种差异的幅度随时间增加。我们的数据表明视网膜中多巴胺能细胞的激活和光诱导的多巴胺释放主要在睁眼后由经典光感受器驱动。
