BULK ISOLATION OF LARGE VENTRAL SPINAL NEURONS

—Cell bodies of spinal neurons can be isolated in bulk fractions, using methods developed for neurons from brain. The technique described here includes sieving steps which allow one to purify and concentrate selectively the larger neuronal perikarya (50 μm or more), most of which could be alpha motoneurons. An average of 170,000 large neurons can be obtained from 50 g of trimmed bovine ventral enlargements. Roughly 6% of the total large neurons in the ventral grey matter are recovered, and 85% of the isolated neurons are larger than 50 μm in their smallest dia. Non-neuronal contaminants, mostly capillary fragments, account for 19% of the total particles in the fraction. Each isolated neuron contains an average of 9690 pg protein and 1353 pg RNA and hydrolyses 2·2 pmol of acetylthiocholine/min. Pretreatment of the spinal tissue with collagenase before cell isolation is also evaluated here.