Since the identification of endogenous H₂S in the mammalian brain in 1989, studies of this molecule uncovered physiological roles in processes such as neuromodulation, vascular tone regulation, cytoprotection against oxidative stress. We previously demonstrated that H₂S induces Ca²⁺ influx in astrocytes by activating transient receptor potential (TRP) channels. During this study we found that H₂S_n activates TRP channels much more potently than does H₂S and that 3-mercaptopyruvate sulfurtransferase produces H₂S₃ and H₂S₂ that activate TRP ankyrin 1 channels Recently, we demonstrated that the chemical interaction of H₂S with nitric oxide (NO) generates H₂S₂ and H₂S₃, and that it gives a mechanism of a synergistic effect between H₂S and NO. Cysteine persulfide (Cys-SSH) together with its glutathione (GSH) counterpart (GSSH) have been proposed to be involved in redox homeostasis. We will also show that 3-mercaptopyruvate sulfurtransferase (3MST) produces Cys-SSH, GSSH, and persulfurated cysteine residues of proteins under physiological conditions together with H₂S_n and H₂S.