2026-06-28T10:13:38Zhttps://docta.ucm.es/rest/oai/request
oai:docta.ucm.es:20.500.14352/181712023-08-10T20:41:49Zcom_20.500.14352_14col_20.500.14352_15
Docta Complutense author Alkozi, Hanan Awad author Pérez de Lara, María Jesús author Pintor, Jesús 2023-06-17T22:10:26Z 2023-06-17T22:10:26Z 2017-09 0014-4835 10.1016/j.exer.2017.06.018 https://hdl.handle.net/20.500.14352/18171 https://doi.org/10.1016/j.exer.2017.06.018 http://www.sciencedirect.com/science/article/pii/S0014483517300684?via%3Dihub Melatonin is a substance synthesized in the pineal gland as well as in other organs. This substance is involved in many ocular functions, giving its synthesis in numerous eye structures. Melatonin is synthesized from serotonin through two enzymes, the first limiting step into the synthesis of melatonin being aralkylamine N-acetyltransferase (AANAT). In this current study, AANAT phosphorylation after the activation of TRPV4 was studied using human non-pigmented epithelial ciliary body cells. Firstly, it was necessary to determine the adequate time and dose of the TRPV4 agonist GSK1016790A to reach the maximal phosphorylation of AANAT. An increase of 72% was observed after 5 min incubation with 10 nM GSK (**p < 0.05, n = 6) with a concomitant rise in N-acetyl serotonin and melatonin synthesis. The involvement of a TRPV4 channel in melatonin synthesis was verified by antagonist and siRNA studies as a previous step to studying intracellular signalling. Studies performed on the second messengers involved in GSK induced AANAT phosphorylation were carried out by inhibiting several pathways. In conclusion, the activation of calmodulin and calmodulin-dependent protein kinase II was confirmed, as shown by the cascade seen in AANAT phosphorylation (***p < 0.001, n = 4). This mechanism was also established by measuring N-acetyl serotonin and melatonin levels. In conclusion, the activation of a TRPV4 present in human ciliary body epithelial cells produced an increase in AANAT phosphorylation and a further melatonin increase by a mechanism in which Ca-calmodulin and the calmodulin-dependent protein kinase II are involved. eng Melatonin synthesis in the human ciliary body triggered by TRPV4 activation: Involvement of AANAT phosphorylation journal article URL https://docta.ucm.es/bitstreams/c39066f0-f4ad-4ed4-b575-27900e9fa83a/download File MD5 6117b36063a8162ae1c7dc54c7c7cc65 1381107 application/pdf Pintor_melatonin synthesis-ExperimentalEyeResearch-Elsevier-2017.pdf