RESUMO
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