Quantification of alpha2A and alpha2C adrenoceptors in the rat striatum and in different regions of the spinal cord.

The alpha2C-adrenoceptor preferring radioligand [3H]-MK912 was used for labelling alpha2A- and alpha2C-adrenoceptors in the rat striatum, in the cervical, thoracic and lumbar parts of the spinal cord, and in the dorsal and ventral halves of the spinal cord. In addition, guanfacine was used as a tool to delineate the alpha2A- and alpha2C-adrenoceptors. In the striatum the sites were 72% alpha2A- and 28% alpha2C-adrenoceptors, while in all regions of the spinal cord the proportions of the sites were about 96% alpha2A- and 4% alpha2C-adrenoceptors. A multi-curve experimental design and computer analysis was used in order to enable the accurate quantification of the alpha2A- and alpha2C-adrenoceptors in the striatum and spinal cord.