Tsunemasa Irie

Protective effect of NGF atelocollagen mini-pellet on the hippocampal delayed neuronal death in gerbils

Very recently, contradictory results were presented as to the effects of exogenous nerve growth factor (NGF) on the hippocampal delayed neuronal necrosis following transient ischemia. In the present study, we administered a large amount of NGF with the atelocollagen mini-pellet system, measured the local NGF contents, and evaluated the effect of this neurotrophic factor on the postischemic hippocampal pyramidal cells in gerbils. We concluded that the exogenous NGF, when given continuously at sufficient concentrations, prevents pyramidal cell damage. The possible cause of discrepancy in previous studies is discussed.

Determination of basal acetylcholine release in vivo by rat brain dialysis with a U-shaped cannula: effect of SM-10888, a putative therapeutic drug for Alzheimer's disease

A U-shaped dialysis cannula was implanted into rat frontal cortex, hippocampus and striatum, and after 1 day for surgical recovery the cannula was perfused with Ringers solution without any acetylcholinesterase (AChE) inhibitor under freely moving conditions. With a highly sensitive assay method for acetylcholine (ACh), the basal ACh content in the dialysates were detectable in those brain regions for several hours. The basal levels in the frontal cortex, hippocampus and striatum were 82 +/- 9, 72 +/- 4, 70 +/- 8 fmol/20 microliters (mean +/- S.E.M.), respectively. When SM-10888, a novel AChE inhibitor and putative therapeutic drug for Alzheimers disease, was injected intraperitoneally, ACh in the dialysate of the cortex increased in a dose-dependent manner. Changes in the levels of hippocampal and striatal ACh release evoked by SM-10888 were similar to, but smaller than, that in the cortex. These data suggest that since the present assay method is able to determine in vivo basal ACh release in the dialysate without any AChE inhibitor, it is possible to study the effect of a novel drug such as SM-10888 in the brain regions.