CHARACTERIZATION AND TRANSPLANTATION OF 2 NEURONAL CELL-LINES WITH DOPAMINERGIC PROPERTIES

Immortalized rat mesencephalic cells (IRB(3)AN(27)) produced dopamine (DA) at a level that was higher than produced by undifferentiated or d ifferentiated murine neuroblastoma cells (NBP2) in culture. Treatment of IRB(3)AN(27) and NBP2 cells with a cAMP stimulating agent increased tyrosine hydroxylase (TH) activity and the intensity of immunostainin g for the DA transporter protein (DAT). IRB(3)AN(27) cells were labell ed with primary antibodies to neuron specific enolase (NSE) and nestin and exhibited very little or no labeling with anti-glial fibrillary a cidic protein (GFAP). IRB(3)AN(27) cells exhibited beta- and alpha-adr enoreceptors, and prostaglandin E(1) receptors, all of which were link ed to adenylate cyclase (AC). Dopamine receptor (D-1) and cholinergic muscarinic receptors linked to AC were not detectable. The levels of P KC alpha and PKC beta isoforms were higher than those of PKC gamma and PKC delta in IRB(3)AN(27) cells. The IRB(3)AN(27) cells were more eff ective in reducing the rate of methamphetamine-induced turning in rats with unilateral 6-OHDA lesion of the nigrostriatal system than differ entiated NBP, cells. The grafted IRB(3)AN(27) were viable as determine d by DiI labelling, but they did not divide and did not produce T-anti gen protein; however, when these grafted cells were cultured in vitro, they resumed production of T-antigen and proliferated after the prima ry glia cells and neurons of host brain died due to maturation and sub sequent degeneration. Examination of H&E stained sections of the graft ed sites revealed no evidence of infiltration of inflammatory cells in the grafted area suggesting that these cells were not immunogenic. Th ey also did not form tumors.