Neurophysiological study for excitatory amino acids-induced neurotoxicity and apoptosis in cultured retinal neurons.

1. 血管活性肠肽（VIP）对谷氨酸诱导视网膜神经元神经毒性的保护作用。VIP （10 nM - 1 muM）呈浓度依赖性减弱谷氨酸诱导的神经毒性。这种保护作用可被VIP受体拮抗剂VIP6-28和蛋白激酶a （PKA）抑制剂H-89拮抗。VIP不影响谷氨酸诱导电流和Ca^<2+>内流。VIP可能通过VIP受体升高cAMP水平，作为谷氨酸诱导视网膜神经元神经毒性的保护因子。激活的PKA可能对谷氨酸神经毒性的下游Ca^<2+>内流有影响。垂体腺苷酸环化酶激活肽（PACAP）对谷氨酸诱导的视网膜神经元神经毒性的保护作用。PACAP27 （10 nM - 1 muM）和PACAP38 （10 nM - 1 muM）呈浓度依赖性的谷氨酸诱导的神经毒性减弱。H-89可抑制PACAPs对有丝分裂原活化蛋白（MAP）激酶的激活。PACAP被认为是通过激活MAP激酶来抑制谷氨酸诱导的神经毒性的神经保护因子，这是由于PKA通过PACAP受体激活所致。磁性细胞分选器（MACS）富集大鼠视网膜神经节细胞（RGCs）。我们展示了一种使用MACS的新的rgc培养技术。它使RGCs在所有视网膜神经元中的含量从0.55%增加到31.0%，并使富集的RGCs存活超过2周。全细胞膜片钳评价表明，在macs分离的RGCs上存在NMDA、kainate和AMIPA三种嗜离子型谷氨酸受体亚型。该培养系统被认为是研究谷氨酸诱导神经毒性的合适模型。

1. Protection of vasoactive intestinal peptide (VIP) against glutamate-induced neurotoxicity in cultured retinal neurons.VIP (10 nM - 1 muM) was attenuated glutamate-induced neurotoxicity in a concentration-dependent manner. This protective effect was antagonized by VIP6-28, a VIP recptor antagonist, and H-89, a protein kinase A (PKA) inhibitor. VIP did not affect glutamate-induced current and Ca^<2+> influx. VIP is suggested to act as a protective factor against glutamate-induced neurotoxicity of retinal neurons by elevating the cAMP level via VIP receptors. Activated PKA might have an effect downstream of the Ca^<2+> influx in glutamate neurotoxicity.2. Protection of pituitary adenylate cyclase activating peptide (PACAP) against glutamate-induced neurotoxicity in cultured retinal neurons.PACAP27 (10 nM - 1 muM) and PACAP38 (10 nM - 1 muM) were attenuated glutamate-induced neurotoxicity in a concentration-dependent manner. Activation of mitogen activated protein (MAP) kinase by PACAPs was inhibited by H-89. PACAPs are suggested to act as neuroprotective factors against glutamate-induced neurotoxicity by activating MAP kinase, which is due to PKA activation via PACAP receptors.3. Rat retinal ganglion cells (RGCs) culture enriched with the magnetic cell sorter (MACS).We demonstrated a new RGC-culture technique using MACS.It enriched RGCs from 0.55 % to 31.0 % of all retinal neurons and enhanced the survival of enriched RGCs for over 2 weeks. The whole-cell patch clamp evaluation was suggested that three ionotropic glutamate receptor subtypes such as NMDA, kainate and AMIPA receptors existed on MACS-separated RGCs. This culture system is thought to be an appropriate model for studying glutamate-induced neurotoxicity in RGC.