THE NEUROTROPHIN NT4 5, BUT NOT NT3, ENHANCES THE EFFICACY OF NIGRAL GRAFTS IN A RAT MODEL OF PARKINSONS-DISEASE/

The neurotrophins NT4/5 and NT3 have previously been shown to improve the survival and fibre outgrowth of embryonic dopaminergic neurons in vitro. In the present study we attempted to augment the efficacy of em bryonic nigral grafts in vivo. This was done by directly infusing the neurotrophins intraparenchymally in close proximity to transplanted ni gral tissue placed in the dopamine depleted striatum of 6-hydroxydopam ine lesioned rats. Our results indicated that NT4/5, but not NT3, stim ulated fibre growth from embryonic nigral cells and enhanced functiona l efficacy of the grafts as assessed by metamphetamine-induced rotatio n.