ABSTRACT
<p><b>OBJECTIVE</b>To provide a useful biological index for clinical diagnosis of Alzheimer's disease (AD) by determination the functional changes in the central cholinergic nerve and their effects on the peripheral lymphatic system.</p><p><b>METHODS</b>The learning and memory impairment model was established through intraventricular injecting quinolinic acid (QA) repeatedly.</p><p><b>RESULTS</b>There was a significant decline of cholineacetyltransferase (ChAT) in cerebral cortex and hippocampus after QA injection. The significantly lower binding activities of acetylcholine muscarinic (M) and nicotinic (N) cholinergic receptors in the hippocampus and cortex in the QA group were found as compared with the sham-operated group (P < 0.01). Similar changes were found in the binding activities of M-and N-receptors on spleen lymphocytes.</p><p><b>CONCLUSION</b>Certain lesion of the central nervous system can be reflected in peripheral spleen lymphocytes, which may be an important reference to diagnose the changes of the central nervous system.</p>