Figure 4.

Proposed scheme by which taurine may affect insulin and GABA release from pancreatic β-cells. In this scheme, 1: taurine is taken up into the β-cells via the taurine transporter (TauT). Once in the cytoplasm, 2: taurine inactivates the ATP-sensitive K⁺-channels either directly via interaction with the sulfonylurea receptor on the channel, or indirectly via an associated protein that binds to the SUR. The inactivation of ATP-sensitive K⁺-channels leads to 3: an increase in intracellular Ca⁺⁺ either via voltage-sensitive calcium channels or mitochondrial buffering. Once there is a critical Ca⁺⁺ concentration, 4: exocytosis of the large dense-core vesicles containing insulin and GABA occurs. In the in vivo pancreas, GABA would bind to GABA_A receptors on α-cells and inactivate glucagon release.