Striatal dopaminergic afferents concentrate in GDNF-positive patches during development and in developing intrastriatal striatal grafts.
Glial cell line-derived neurotrophic factor (GDNF) has potent trophic action on fetal dopaminergic neurons. We have used a double immunocytochemical approach with antibodies that recognize GDNF and tyroxine hydroxylase (TH) or the phosphoprotein DARPP-32, to study the developmental pattern of their interactions in the rat striatum and in intrastriatal striatal transplants. Postnatally, at one day and also at 1 week, GDNF showed a patchy distribution in the striatum, together with a high level of expression in the lateral striatal border, similar to that observed for the striatal marker DARPP-32 and also for TH. In the adult striatum, there was diffuse, weak immunopositivity for GDNF, together with widespread expression of DARPP-32-positive neurons and TH-immunoreactive (TH-ir) fibers. In 1-week-old intrastriatal striatal transplants, there were some GDNF immunopositive patches within the grafts and although there was not an abundance of TH-positive fibers, the ones that were seen were located in GDNF-positive areas. This was clearly evident in 2-week-old transplants, where TH-ir fibers appeared selectively concentrated in GDNF-positive patches. This pattern was repeated in 3-week-old grafts. In co-transplants of mesencephalic and striatal fetal tissue (in a proportion of 1:4), TH-ir somata were located mainly at the borders of areas that were more strongly immunostained for GDNF, and TH-ir fibers were also abundant in these areas and were found in smaller numbers in regions that were weakly positive for GDNF. These results demonstrate that GDNF-ir is coincident with that for TH and DARPP-32, and suggest that GDNF release by fetal striatal neurons both in normal development and in developing striatal grafts may have not only a trophic but also a tropic influence on TH-ir fibers and may be one of the factors that regulate dopaminergic innervation of the striatum.
López-Martín
E
E
Department of Morphological Sciences, University of Santiago de Compostela, Galicia, Spain.
Caruncho
H J
HJ
Rodríguez-Pallares
J
J
Guerra
M J
MJ
Labandeira-García
J L
JL
D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development* / Q000378:metabolism / Q000502:physiology; D017690:Cell Transplantation; D003342:Corpus Striatum / Q000378:metabolism / Q000502:physiology*; D004298:Dopamine / Q000378:metabolism*; D051100:Glial Cell Line-Derived Neurotrophic Factor; D008636:Mesencephalon / Q000166:cytology; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009475:Neurons, Afferent / Q000502:physiology* / Q000637:transplantation*; D051381:Rats; D017207:Rats, Sprague-Dawley
C495041:Gdnf protein, rat; D051100:Glial Cell Line-Derived Neurotrophic Factor; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D004298:Dopamine