Homozygous GAD65 and heterozygous GAD67 knock-out mice reveal normal retinal development and maintenance despite reduced amounts of GAB A

摘要

The key enzyme for GABA synthesis is glutamate decarboxylase (GAD) that appears in two isoforms which are named according to their molecular weight as GAD65 and GAD67. Several studies suggest that these two enzymes may have distinct roles in neuronal function. For instance, GAD67 is a cytosolic enzyme distributed throughout the cell, whereas GAD65 is reversibly bound to the membrane of synaptic vesicles . Brains of GAD67 knock-out mice contain approximately 10% of normal GABA levels at birth. In mice lacking GAD65 there is only a small decrease in the total GABA content during early postnatal development, whereas the GABA content was reduced to 50% at 4 months of age .