1 research outputs found
Lesioning of the Striatum Reverses Motor Asymmetry in the 6-Hydroxydopamine Rodent Model of Parkinsonism
In the rat several paradigms of grafting of adrenal
medulla into the striatum were studied following the
induction of a parkinsonian model, using a unilateral
6-hydroxydopamine (6-OHDA) lesion of the substantia nigra
. Direct autologous grafting of adrenal medulla
into the caudate-putamen complex, a radiofrequency
lesion of the striatum alone, and a radiofrequency
lesion followed by delayed grafting of adrenal medulla
were compared by analyzing rotational behavior.
Direct grafting of adrenal medulla produced an
overall reduction in apomorphine induced turning
behavior by 43.5% when compared with controls.
Radiofrequency lesioning of the striatum without
graft showed the best improvement over control
animals with a 92% reduction in the total number of
rotations induced by apomorphine. Delayed grafting
into the caudate lesion cavity also produced a
dramatic reduction in motor asymmetry but did not
improve the behavioral outcome over that of the
lesion alone. Animals receiving only radiofrequency
lesions exhibited a band of increased tyrosine
hydroxylase like immunoreactivity bordering the
lesion cavity. Graft survival was limited in the nonlesioned
animals but appeared enhanced in the
animals whose striatum was previously lesioned.
Lesion location within the striatum influenced the
behavioral outcome. Large reductions in
apomorphine-induced rotations could result from
small lesions of the dorso-lateral striatum. These
findings indicate that selective destruction of the
caudate-putamen complex without tissue
transplantation produces a dramatic reduction in the
motor asymmetry of 6-OHDA treated rats. Suggested
explanations for the decrease in induced rotational
behavior with radiofrequency lesions include a
decrease in the number of striatal dopamine
receptors following cell destruction and lesioninduced
recovery of host dopaminergic afferents.
Striatal damage in critical areas can reverse some of
the motor behavior associated with the 6-OHDA
model and needs to be considered when evaluating
the effects of neural grafting in this model