PHOSPHODIEASERASE INHIBITION DECREASES NEURONAL

• Project/Area Number: 12671422
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Orthopaedic surgery
• Research Institution: Ehime University
• Principal Investigator: OGATA Tadanori Ehime University, School of Medicine, Instructor, 医学部, 助手 (30291503)
• Co-Investigator(Kenkyū-buntansha): MATSUDA Yoshiro Ehime University, School of Medicine, Associate Professor, 医学部, 助教授 (70110830)
• Project Period (FY): 2000 – 2001
• Project Status: Completed (Fiscal Year 2001)
• Budget Amount: ¥2,000,000 (Direct Cost: ¥2,000,000); Fiscal Year 2001: ¥900,000 (Direct Cost: ¥900,000); Fiscal Year 2000: ¥1,100,000 (Direct Cost: ¥1,100,000)
• Keywords: spinal cord / nitric oxide / neuron / cyclic GMP / phosphodiesterase / phosphodiesterase / cyclic AMP / TNF-α / アストロサイト / マイクログリア

Research Abstract

The effect of intracellular cyclic GMP increase on neuronal damage was tested using a newly developed nitric oxide-related injury model of cultured spinal cord neurons. Neuronal damage after 24 hours' exposure to sodium nitroprusside (SNP, 6.25-100 μM), an NO donor, was evaluated by measuring the activity of released lactate dehydrogenase (LDH) from degenerated neurons. The intracellular cyclic GMP increase caused by the addition of 100 μM 8-bromo-cyclic GMP, a cell membrane permeable cyclic GMP, strongly inhibited the neuronal damage induced by 10 μM SNP, although 8-bromo-cyclic AMP yielded no effect. The addition of 8-bromo-cyclic GMP induced nerve growth factor (NGF) production in cultured neurons, suggesting that the neuroprotection via intracellular cyclic GMP increase is mediated by NGF production. The addition of propentofylline (PPF; 1-100 μM), a xanthine derivative and phosphodiesterase (PDE) inhibitor, enhanced intracellular cyclic GMP elevation induced by SNP exposure. The neuronal damage induced by 10 μM SNP exposure for 24 hours was almost completely blocked in the presence of PPF.