Morphological and histoenzymatic changes in cells of the spinal cord and spinal ganglia after epidural injection of a combination of prosidol with clonidine were studied on dogs. No pathological structural and metabolic changes in the nervous tissue were found after combined treatment with the test drugs. Higher activity of nucleic acids and alkaline phosphatase in spinal neurons and spinal ganglion in experimental animals in comparison with those in controls indicates intensification of protein synthesis and active transport in the endothelium of nerve tissue capillaries, which is a favorable factor.