GABA can inhibit the secretion of glucagons by a-cells61 and stimulate the expression of glutamate decarboxylase(65) (GAD65) . GAD65 will stimulate P-cells to produce GAD. Then GAD catalyzes the decarboxylation of glutamate to synthesize GABA . This mechanism has the feedback function to inhibit the activity of GAD . 8 Pancreatic GAD65 was identified as a target antigen for autoantibody found in blood circulation of patients with insulin-dependent diabetes mellitus (IDDM) . Other studies have shown that streptozotocin-induced diabetes brought about an imbalance in GABA metabolite concentration in the ventromedial hypothalamus 62 Pancreatic islet binding sites for GABA and benzodiazepines have been shown to be of functional significance in the secretion of insulin in rodents and humans A decrease in GABA concentration in pancreatic islet cells was associated with the decline of insulin synthesis and release levels present in diabetes .14 The functions of GABA and GAD in pancreatic P-cells are still unclear, but GABA is considered to have a primary role as a signaling molecule in the pancreatic islets
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