Receptor characteristics and recovery of function following kainic acid lesions and fetal transplants of the striatum. II. Dopaminergic systems

This experiment reports the development of striosomal-like patches in fetal striatal transplants grafted either into the intact, or kainic acid-lesioned, striatum of adult female rat brain. Although D2 receptor density approached control levels in the area of the patches, otherwise the transplanted striatum was relatively empty of dopamine receptors, and overall D2 development of the graft was strikingly reduced from controls. Transplants reversed lesion-induced hyperactivity under saline, but not amphetamine/apomorphine conditions, and led to an increased sensitivity of lesion and grafted animals following haloperidol injection. Transplants into the intact brain led to a lesion-like effect. M1 muscarinic cholinergic/D2 receptor density inversely correlated with activity after saline injection. These results suggest that abnormal maturation of the grafted striatum correlates with deficits in activity in grafted animals, and suggests that abnormal transplant development significantly impacts on transplant-induced behavioral changes.