Effect of Hydrogen Sulfide on Sympathetic Neurotransmission and Catecholamine Levels in Isolated Porcine Iris-Ciliary Body

摘要

Abstract In the present study, we investigated the pharmacological action of hydrogen sulfide (H_2S, using sodium hydrosulfide, NaHS, and/or sodium sulfide, Na_2S as donors) on sympathetic neurotransmission from isolated, superfused porcine iris-ciliary bodies. We also examined the effect of H_2S on norepinephrine (NE), dopamine and epinephrine concentrations in isolated porcine anterior uvea. Release of [~3H]NE was triggered by electrical field stimulation and basal catecholamine concentrations was measured by high performance liquid chromatography (HPLC). Both NaHS and Na_2S caused a concentration-dependent inhibition of electrically evoked [~3H]NE release from porcine iris-ciliary body without affecting basal [~3H]NE efflux. The inhibitory action of H_2S donors on NE release was attenuated by aminooxyacetic acid (AOA) and propargyglycine (PAG), inhibitors of cystathionine beta-syn-thase (CBS) and cystathionine gamma-lyase (CSE), respectively. With the exception of dopamine, NaHS caused a concentration-dependent reduction in endogenous NE and epinephrine concentrations in isolated iris-ciliary bodies. We conclude that H~2S can inhibit sympathetic neurotransmission from isolated porcine anterior uvea, an effect that is dependent, at least in part, on intramural biosynthesis of this gas. Furthermore, the observed action of H~2S donors on sympathetic transmission may be due to a direct action of this gas on neurotransmitter pools