[The development of a high sensitivity and high linearity fluorescence microphotometry system for distribution analysis of neurotransmitter in the brain].

A new fluorescence microphotometry system was developed for analysis of the distributions and amounts of neurotransmitter and its related chemical substances in the smaller brain regions. This system can measure fluorescence intensity of 10,000 points in animal brain slices which were immunohistochemically and histochemically stained. This system mounts a photomultiplier tube of high sensitivity and high linearity to a detector; therefore, this system surpasses in quantitative capability by two figures compared with an image analyzer which uses a high-sensitivity TV camera. The high-precision step-motor scanning stage moves under the objective lens of the fluorescence microscope and analyzes the entire surface of the slice: measuring speed, 250 points/min; maximum measuring area, 76 X 52 mm. The data of fluorescence intensity and position (X and Y value) on the slice are transmitted to a computer, calculated statistically and displayed two- and three-dimensionally. In this study, immunohistochemical distribution and intensity of acetylcholine, choline acetyltransferase and acetylcholinesterase in the rat cervical spinal cord were measured. The distributions of their chemical substances are consistent with previous observations. This system is applicable to a wide range of neuroscience studies.