Immunohistochemical localization of DARPP-32 in the brain of the turtle, Pseudemys scripta elegans: further assessment of its relationship with dopaminergic systems in reptiles.
A previous study in the lizard Gekko gecko has revealed that the distribution of DARPP-32 (a phosphoprotein related to the dopamine D(1)-receptor) largely resembles the pattern observed in birds and mammals, at least as far as basal ganglia structures are concerned. On the other hand, several specific features of DARPP-32 distribution in the gekkonid brain were noted that deserved further attention, e.g. cellular co-localization of DARPP-32 and tyrosine hydroxylase (TH) immunoreactivity in hypothalamic and caudal rhombencephalic areas. To assess the primitive or derived character of these features, DARPP-32 and TH antibodies have been applied to the brain of the turtle, Pseudemys scripta elegans, which belongs to a different radiation of reptiles. Areas in Pseudemys that are densely innervated by TH-immunoreactive fibers, such as the striatum and amygdaloid complex, display strong immunoreactivity for DARPP-32 in somata and neuropil. Strongly immunoreactive fiber plexuses were found in the substantia nigra pars reticulata and in the ventromedial part of the rhombencephalon. Cellular co-localization of DARPP-32 and TH was observed in the ventral hypothalamus but, in contrast to Gekko, not at caudal rhombencephalic levels. Moreover, cellular DARPP-32 immunoreactivity was not seen in the raphe nuclei and spinal cord of Pseudemys. Other notable species differences in DARPP-32 distribution were found in the olfactory bulb, dorsal ventricular ridge and pretectum. In conclusion, the present account on the distribution of DARPP-32 in Pseudemys confirms and extends previous findings in a gekkonid lizard. At the same time, however, it demonstrates that substantial species differences exist, some of which may be related to differences previously observed in the dopaminergic systems.
Smeets
Wilhelmus J A J
WJ
Department of Anatomy, The Graduate School of Neurosciences Amsterdam, Research Institute of Neurosciences, Vrije Universiteit Medisch Centrum, Van Der Boechorststraat 7, BT-1081 Amsterdam, The Netherlands. wjaj.smeets.anat@med.vu.nl
Lopez
Jesus M
JM
González
Agustín
A
D000818:Animals; D001923:Brain Chemistry / Q000502:physiology*; D004298:Dopamine / Q000032:analysis*; D051937:Dopamine and cAMP-Regulated Phosphoprotein 32; D007150:Immunohistochemistry; D008116:Lizards / Q000033:anatomy & histology / Q000502:physiology*; D009419:Nerve Tissue Proteins; D009474:Neurons / Q000737:chemistry*; D010750:Phosphoproteins / Q000032:analysis*; D013045:Species Specificity; D014426:Turtles / Q000033:anatomy & histology / Q000502:physiology*
D051937:Dopamine and cAMP-Regulated Phosphoprotein 32; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins; D004298:Dopamine