Abstract
Purpose: :
Serotonin (5-Hydroxytryptamine: 5-HT) is a biogenic amine with a wide spectrum of effects. Recently it has been implicated in the maintenance of the intraocular pressure by joining to its receptors. In this work we deal with analysing the 5-HT and its metabolic by product 5-Hydroxiindolacetato (5-HIAA) concentrations in relation to primary open angle glaucoma (POAG).
Methods: :
A prospective longitudinal study was done in 60 patients of both sexes (aged 50 to 90 years) which were selected according to the inclusion/exclusion criteria. Patients were programmed for anti-glaucomatous surgery (GG; n=30) or cataracts surgery (GC; n=30). The aqueous humor was obtained (0,2 ml) at the onset of surgical maniouvres, frozen (-80ºC) and stored until processing. Samples were diluted with perchloric acid 0,2N (1:3 v/v), microfiltered throughout 0,2 µm and centrifuged x10.000 (4ºC for 5 minutes). The 5-HT and 5-HIAA concentrations were determined by high performance liquid chromatograpy (HPLC) with electrochemical detection, by comparison with standard times and performing standard curves with 5-HT ( r=0,0004) and 5-HIAA (r=0,0003).
Results: :
The 5-HT levels were higher in the GG than in the CG, without statistical differences between groups (p>0,05). However, the results from the 5-HIAA levels were significantly higher in the GG than in the CG (p<0,05).
Conclusions: :
Serotonin has been biochemically found in the human aqueous humor. The 5-HT and 5-HIAA levels appeared different in the glaucomatous patients than in the CG. Probably the 5-HT-derived vascular and nervous system actions and its relationship to melatonin availability may influence the retinal and choroidal vasculature and the ganglion cell survival. Further research on neurotransmitters and other related molecules may guide new managing strategies for avoiding glaucomatous progression and blindness
Keywords: aqueous • neurotransmitters/neurotransmitter systems • clinical laboratory testing