Preferential alterations in the mesolimbic dopamine pathway of heterozygous reeler mice: an emerging animal-based model of schizophrenia.
Based on a number of neuroanatomical and behavioural similarities, recent evidence suggests that heterozygous reeler mice, haploinsufficient for reelin expression, represent a useful model of psychosis vulnerability. As brain mesolimbic dopamine pathways have been proposed to be associated with the pathophysiology of psychotic disorders, we thought it would be of interest to examine whether these animals present disturbances in the mesolimbic dopamine system. To this end we studied by immunocytochemical, in situ hybridization procedures and receptor autoradiography, several markers of the mesotelencephalic dopamine pathway in heterozygous reeler mice and controls. We report that heterozygous reeler mice exhibit a reduction in the number of tyrosine hydroxylase-immunoreactive cell bodies and tyrosine hydroxylase mRNA levels in the ventral tegmental area, as well as a reduction of tyrosine hydroxylase and dopamine transporter immunoreactivity in the dopamine terminal fields of the limbic striatum. In these areas we also observed a reduction of dopamine D2 receptor mRNA. Finally, a marked increase in D3 receptor mRNA levels was observed concomitant with a significant increase in D3 binding sites. On the contrary, the nigrostriatal pathway did not show any significant alteration in heterozygous reeler mice with regards to the dopaminergic markers examined in substantia nigra cell bodies and dorsal striatum dopamine terminal fields. These results suggest a specific link between reelin-related neuronal pathology and dopamine involvement in the pathophysiology of psychotic disorders.
Ballmaier
Martina
M
Division of Pharmacology, Department of Biomedical Sciences and Biotechnologies, Brescia University Medical School, Via Valsabbina 19, 25123 Brescia, Italy.
Zoli
Michele
M
Leo
Giuseppina
G
Agnati
Luigi Francesco
LF
Spano
PierFranco
P
D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects / Q000502:physiology; D015415:Biomarkers / Q000032:analysis; D004195:Disease Models, Animal; D004298:Dopamine / Q000378:metabolism*; D050483:Dopamine Plasma Membrane Transport Proteins; D005260:Female; D006579:Heterozygote; D008297:Male; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins / Q000378:metabolism; D051379:Mice; D008818:Mice, Neurologic Mutants; D009419:Nerve Tissue Proteins; D009434:Neural Pathways / Q000254:growth & development / Q000378:metabolism* / Q000473:pathology; D009474:Neurons / Q000378:metabolism* / Q000473:pathology; D009714:Nucleus Accumbens / Q000254:growth & development / Q000378:metabolism* / Q000473:pathology; D017729:Presynaptic Terminals / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011869:Radioligand Assay; D011954:Receptors, Dopamine / Q000235:genetics; D000091042:Reelin Protein; D012559:Schizophrenia / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D014446:Tyrosine 3-Monooxygenase / Q000235:genetics / Q000378:metabolism; D017557:Ventral Tegmental Area / Q000254:growth & development / Q000378:metabolism* / Q000473:pathology
D015415:Biomarkers; D050483:Dopamine Plasma Membrane Transport Proteins; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D011954:Receptors, Dopamine; D000091042:Reelin Protein; D014446:Tyrosine 3-Monooxygenase; C000717128:Reln protein, mouse; D004298:Dopamine