An improved method for the bulk isolation of spinal motoneurones.

Details are described of a procedure for the isolation of motoneurones from pig spinal cord in high yield and high purity. Mechanical dissociation, one low-speed centrifugation and two high-speed ultracentrifugations were applied to separate the motoneurons from other elements of the anterior horn. The first ultracentrifugation through a sucrose gradient resulted in a pellet consisting mainly of motoneurones, microvessels, free nuclei and red blood cells, whereas with the use of Ficoll 400 the motoneurones could be separate from the contaminating elements during a second ultracentrifugation. The high yield and purity of the motoneurones in the final fraction may permit further studies, in which the neurochemical properties of the spinal motoneurones can be elucidated.