Regulation of Hydrogen Sulfide Levels by Cannabinoids in the Bovine Isolated Retina

Abstract

Both endocannabinoids and hydrogen sulfide (H2S) have been reported to exert neuroprotective actions in neural tissues (Biermann et al., Mol Vis. 2011;17:1275–86; Nucci et al., Invest Ophthalmol Vis Sci. 2007;48(7):2997–3004). It remains to be determined if these modulators can interact with each other and/or share a common pathway in their neuroprotective actions.PurposeThe aim of the present study was, therefore, to investigate the pharmacological actions of endocannabinoids on the biosynthesis of H2S in isolated bovine neural retina.MethodsIsolated bovine retinae were homogenized and exposed to different concentrations of methanandamide (1 nM – 10 uM) and 2‐arachidonyl glycerol (2‐AG) (1 – 3 uM) for 90 minutes at 37ºC. Retinal homogenates were then incubated with ethylenediaminetetraacetic acid (EDTA) (1%), Zinc acetate (1%), and Borate buffer (pH 11) for 30 mins followed by 10‐minute incubation with N, N dimethyl p‐phenylenediamine (20 mM) and FeCl3 (300 mM). Samples were then centrifuged at 5000 g for three minutes and supernatant was assessed for H2S content using the well‐established Methylene Blue method.ResultsBoth methanandamide and 2‐AG elicited a concentration‐dependent decrease in basal H2S production in the isolated retina. For instance, methanandamide (10 μM) significantly (p <0.05) reduced basal production of H2S by 30% when compared to controls. Likewise, 2‐AG (10 μM) also elicited a 30% decrease in basal retinal H2S concentration when compared to controls.ConclusionsWe conclude that exogenously applied endocannabinoids can alter the basal production of H2S in the isolated neural retina. The observed effect of endocannabinoids on the pathway leading to H2S biosynthesis suggests that a cross‐talk exists between both neuromodulators in the retina.Support or Funding InformationSupported by NIH/NEI Research Grant 1R15EY022215‐01This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.