Regional [3H]acetylcholine and [3H]nicotine binding in developing mouse brain

Abstract

The postnatal development of nicotine-like binding sites in the cortex, hippocampus, midbrain and cerebellum of 3-, 7-, 12-, 17- and 30-day-old mice was studied. Two different nicotinic cholinergic ligands, namely [3H]acetylcholine ([3H]ACh) and [3H]nicotine ([3H]NIC) were used to detect the nicotine-like binding sites in in vitro binding assays. The postnatal development of the binding sites of [3H]NIC increased gradually with age in all brain regions studied. The [3H]ACh binding, on the other hand, showed a marked peak on day 12 in the cerebellum and midbrian but did not change notable with age in the hippocampus and cortex, except for a slight temporary increase in the cortex on day 7. The time-course for the appearance of nicotinic binding sites as observed with [3H]ACh was found to be rather similar to that earlier described for [3H]alpha-bungarotoxin binding sites, whereas that for [3H]NIC differed from that described for other nicotinic ligands.