The effects of various receptor agonists/antagonists on the accumulation of inositol phosphates(InsPs) in cultured rat retinal pigment epitheium (RPE) cells were analysed. The results showed that serotonin and the 5-HT2 agonists such as alpha;-methyl-serotonin, quipazine, and DOI (1-[2.5-dimethoxy-4-iodopheny1]-2-aminopropane) all stimulated InsPs accumulation in rat RPE cells. The serotonin-induced stimulation of InsPs was effectively blocked by ketanserin, a 5-HT2 antagonist, but also attenuated by the active phorbol ester PMA (4ft-phorbol 12-myristate 13-acetate), a potent protein kinase C activator.The data presented provide clear evidence for the presence of 5-HT2 receptors coupled to phosphoinositide metabolism on cultured rat RPE cells.
（Chin J Ocul Fundus Dis,1994,10:80-83）
Geographic atrophy (GA), the late-stage of non-neovascular age-related macular degeneration, is characterized by progressive degeneration of photoreceptors, retinal pigment epithelium, and the choriocapillaris, ultimately leading to irreversible central vision loss. Advances in multimodal imaging, particularly the optical coherence tomography (OCT) based definition of complete retinal pigment epithelium and outer retinal atrophy (cRORA), have substantially improved the diagnostic consistency of GA. The recent approval of complement inhibitors, pegcetacoplan (complement C3 inhibitor) and avacincaptad pegol (complement C5 inhibitor) marks a treatment milestone, demonstrating efficacy in slowing atrophy progression. However, the efficacy of existing drugs still mainly focuses on structural endpoints, with limited protective effects on functions. This reveals the core challenge of "structural-function dissociation" in GA. In recent years, attention has been drawn to early endpoints such as incomplete retinal pigment epithelium and outer retinal atrophy transforming into cRORA; sensitive functional assessment tools such as micro-perimetry, as well as artificial intelligence-assisted OCT stratified analysis and individualized progression prediction models, have also continuously expanded the assessment and management capabilities of GA. Additionally, diverse treatment strategies such as gene therapy, stem cell transplantation, and neurotrophic protection are also being actively explored, further broadening the future intervention pathways. It is worth noting that the prevalence and clinical manifestations of GA in Asian populations are significantly different from those in Western populations, suggesting that the disease characteristics and mechanisms may have racial specificity. Currently, there is a lack of systematic local data in China, and it is urgent to establish a multicenter longitudinal cohort based on cRORA criteria, and incorporating multimodal imaging and functional assessments, to facilitate GA characterization, risk prediction, and the development of individualized intervention strategies in the Chinese population.
