The physiological basis of transplantation of fetal catecholaminergic neurons in the transected spinal cord of the rat

Abstract

1. 1. Fetal (E.17) rat locus coeruleus and mesencephalic dopaminergic neurons when implanted into the transected spinal cord of the young adult rat survive for periods of longer than four months. Axons of up to 15 mm in length are observed growing from the cell bodies of the implanted neurons. 2. 2. Fluorescent catecholaminergic (presumably dopaminergic) cell bodies are found in the caudal region of the transected, non-implanted spinal cord. 3. 3. After transection of the spinal cord at the middle thoracic region in rats, at different postnatal ages (PN. 0, 7, 14, 21 and 28), there is substantial recovery of motor coordination involving all four limbs in the PN. 0 and PN. 7 groups. Recovery is best in the PN. 7 group. There is almost no recovery in the PN. 28 group, and very little recovery in the PN. 14 and PN. 21 groups. 4. 4. Spinal locomotor generators in rat can, therefore, display a substantial degree of functional autonomy, if the spinal cord is cut before a certain critical stage of development (before PN. 14). These results have interesting implications with regard to current efforts to understand the mechanisms that regulate the spinal locomotor generators in experimental animals, and perhaps in man as well.