The autoradiographic binding of [3H] quinuclidinyl benzilate to muscarinic receptors in the spinal cord of the sheep

Autoradiography of [3H] quinuclidinyl benzilate was used to demonstrate the distribution of muscarinic acetylcholine binding in the spinal cord of sheep. Binding was confined to the grey matter of the cord, and was most densely distributed in the substantia gelatinosa region of the dorsal horn, the lamina X region around the central canal, the intermediolateral columns and in various regions of the ventral horn. The use of specific M1 and M2 receptor subtype ligands, pirenzipine and 4-DAMP indicated that both receptor subtypes were present in most regions of dense binding.