Autoradiographic localization of muscarinic cholinergic receptors in visual areas of cat brain: Variations in sensitivity of N-( super(3)H)methylscopolamine binding sites to carbachol and pirenzepine

The distribution of muscarinic acetylcholine receptors (MChRs) was studied in visual areas of cat brain using in vitro quantitative autoradiography with 1 nM N-( super(3)H)methylscopolamine (( super(3)H)NMS) as a radioligand. The highest density of ( super(3)H)NMS binding was observed in lamina A of the lateral geniculate nucleus (LGN) and in layer II/III of the visual cortex. The lowest binding was seen in the stratum griseum intermediale of the superior colliculus (SC). The SC and LGN contain predominantly M sub(2) sites.