QUANTIFICATION OF ALPHA(2A) AND ALPHA(2C) ADRENOCEPTORS IN THE RAT STRIATUM AND IN DIFFERENT REGIONS OF THE SPINAL-CORD

The alpha(2C)-adrenoceptor preferring radioligand [H-3]-MK912 was used for labelling alpha(2A)- and alpha(2C)- adrenoceptors in the rat stri atum, in the cervical, thoracic and lumbar parts of the spinal cord, a nd in the dorsal and ventral halves of the spinal cord, in addition, g uanfacine was used as a tool to delineate the zeta(2A)- and alpha(2C)- adrenoceptors. In the striatum the sites were 72% alpha(2A)- and 28% a lpha(2C)-adrenoceptors, while in all regions of the spinal cord the pr oportions of the sites were about 96% alpha(2A)- and 4% alpha(2C)-adre noceptors. A multi-curve experimental design and computer analysis was used in order to enable the accurate quantification of the alpha(2A)- and alpha(2C)-adrenoceptors in the striatum and spinal cord.