Acetylcholine contents and muscarinic receptor levels in frontal cortex, corpus striatum, and hippocampus of reserpinized rats and mice

The acetylcholine (ACh) levels in rat and mouse frontal cortex increased 155% and 124%, respectively, 24 h after ip reserpine 3 mg.kg-1. Striatal ACh contents, however, were diminished by 47% in rats and 80% in mice. ACh contents elevated 50% and scopolamine (Scop) depleted the ACh by 47% in mouse striatum 12 h following reserpine. Receptor binding assay showed that 24 h after reserpine the Bmax of [3H]quinuclidinyl benzilate ([3H]QNB) binding to muscarinic receptors increased in frontal cortex (by 33% in rats, by 30% in mice) and decreased in striatum (31% in rats, 26% in mice). In mouse hippocampus the ACh contents, Bmax, and affinity of muscarinic receptors lowered 63%, 19%, and 26%, respectively. But these changes were not seen in rat hippocampus.