Behavioral effects of adrenal medullary transplants in non-human primates

Small multiple "ribbon" autografts of intact adrenal medulla stereotaxically implanted at several sites throughout the striatum in longtailed macaques (Macaca fascicularis) have been shown to contain large amounts of viable glandular tissue as long as eight weeks after transplantation. Variations of technique clearly influence viability. All monkeys were maintained in specially adapted rotometer cages so that 24-hour measurements of activity and directional bias could be gathered. Lesions induced by intracerebral injection of 6-hydroxydopamine in the substantia nigra produced the expected chronic decrease in percentage of contralateral turning in most of the 24 subjects. Animals that received the longest viable ribbon grafts showed a reversal of this effect back toward base line, whereas monkeys whose grafts left little or no surviving tissue showed no behavioral improvement.