Objective It was designed to observe the effects of ? amyloid protein on the functions of neurotransmitter receptors and to disclose the possible pathophysiological mechanism of Alzheimer disease(AD) mediated by ? amyloid protein and neurotransmitter receptors. Methods Messenger RNA was taken from brains of aged Wistar rats with Promega kits and microinjected into Xenopus oocytes for receptor expression. The currents of expressed receptors and the effects of A? 1 40 on them were detected with the double electrode voltage clamps technique. Results ACh, glutamate, dopamine and GABA receptors were successively expressed in Xenopus oocytes. The currents of these expressed receptors detected with voltage clamps were carried by chloride ions with their equibrillium potentials close to 22 mV. Currents of expressed ACh, glutamate, dopamine receptors in the aged rats decreased more significantly than those in adult young rats. A? had a reverse effect on the functions of ACh and glutamic acid receptors. A? 1 40 enhanced significantly the currents of expressed glutamate receptors when it inhibited markedly the currents of expressed ACh receptors. The currents induced by 10 -4 mol/L ACh decreased from (90.90?14.14) nA to (80.67?16.24) nA ( P

BACKGROUND: More attention has been paid upon the injury effect resulted from the decrease of superoxide dismutase(SOD) activity and increase of malonaldehyde (MDA) content in brain. Whether pig brain peptide solution can pass blood-brain barrier and penetrate into brain tissue and protect brain nerve is still found in limited cases reports. Relevant reports are still rare both in China and abroad.OBJECTIVE: To explore the effect of pig brain peptide solution on SOD activity and MDA content in brain and liver of senile model mice made by D-galactose.DESIGN: Experimental animals-based randomized and controlled experimental observation.SETTING: Institute of Senile Medical of General Hospital of Chinese PLA.MATERIALS: The experimant was made in the Institute of Senile Medical (Chinese PLA key laboratory) of General HosPital of Chinese PLA from February to April 2001. Totally 82 NH mice, weighted from 18 to 22 g, half male and half female, were provided by the Medical Experimental Animal Center of General Hospital of Chinese PLA. These mice were randomly divided into the control group, hige dose group, middle dose group, low dose group, aniracetam group (positive control group), and D-galactose group.METHODS: Each group was given drugs seperately for 6 weeks. The senile mice model was induced by D-galactose. SOD activity of each group was checked with chemiluminescence method and MDA content examined with thiobarbituric acid colourimetry method.MAIN OUTCOME MEASURES: SOD activity and MDA content of mice in each group.RESULTS: Pig brain peptide solution with high and middle doses significantly increased SOD activity[ (30.23 ± 5.23), (29.65 ± 4. 88 );(19. 84 ± 5.79), (16.75 ± 5.32) μkat/g respectively], and decreased MDA content[ (630.00 04; 8(34): 7748-50CONCLUSION: Pig brain peptide solution has obvious antioxidative effect, and has certain protective effects on brain nerve cells and liver cells of senile mice.