title: Immunohistochemical localization of DARPP-32 in the brain of the lizard, Gekko gecko: co-occurrence with tyrosine hydroxylase.
abstract: To assess the relationship between dopaminergic neuronal structures and dopaminoceptive structures in a reptile, single and double immunohistochemical procedures with antibodies directed against DARPP-32 (dopamine- and cAMP-regulated phosphoprotein with an apparent molecular mass of 32,000 daltons),a phosphoprotein related to the dopamine D(1)-receptor, and tyrosine hydroxylase (TH) were applied to the brain of the lizard, Gekko gecko. The DARPP-32 antibody yielded a well-differentiated pattern of staining in the brain of Gekko. In general, areas that are densely innervated by TH-immunoreactive, putative dopaminergic fibers, such as the nucleus accumbens, striatum, dorsal ventricular ridge, and amygdaloid complex, display strong immunoreactivity for DARPP-32 in somata and neuropil. Distinct cellular DARPP-32 immunoreactivity was also found in the lateral cortex, ventral hypothalamus, habenula, central nucleus of the torus semicircularis, midbrain tectum, parvicellular isthmic nucleus, raphe nuclei, caudal rhombencephalic tegmentum, and spinal cord. Striatal projections to the midbrain and their target, i.e., the substantia nigra pars reticulata, were found to be strongly immunoreactive. Double immunofluorescence staining revealed that dopaminergic cells generally do not stain for DARPP-32, except for cells in the ventral hypothalamus and at caudal rhombencephalic levels. In conclusion, the distribution of DARPP-32 in the brain of the lizard Gekko gecko largely resembles the pattern observed in birds and mammals, at least as far as basal ganglia structures are concerned. On the other hand, there are several specific features of DARPP-32 distribution in the gekkonid brain that deserve further attention, such as cellular colocalization of DARPP-32 and TH immunoreactivity in hypothalamic and caudal rhombencephalic areas, and cellular DARPP-32 immunoreactivity in the tectum and central nucleus of the torus semicircularis of the midbrain, the superior and inferior raphe nuclei, and the spinal cord.
authors.affiliation: The Graduate School of Neurosciences Amsterdam, Research Institute of Neurosciences and Department of Anatomy, Vrije Universiteit, Amsterdam, The Netherlands. wjaj.smeets.anat@med.vu.nl
authors.forename: W J
authors.initials: WJ
authors.lastname: Smeets
authors.forename: J M
authors.initials: JM
authors.lastname: Lopez
authors.forename: A
authors.initials: A
authors.lastname: González
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D001933:Brain Stem / Q000378:metabolism; D051937:Dopamine and cAMP-Regulated Phosphoprotein 32; D007150:Immunohistochemistry; D008116:Lizards / Q000378:metabolism*; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins / Q000378:metabolism*; D013116:Spinal Cord / Q000378:metabolism; D014018:Tissue Distribution; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
chemical_list: D051937:Dopamine and cAMP-Regulated Phosphoprotein 32; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins; D014446:Tyrosine 3-Monooxygenase