title: Reduction in parvalbumin expression in the zona incerta after 6OHDA lesion in rats.
abstract: In an effort to understand better the neurochemical changes that occur in Parkinson disease, we have examined the expression patterns of the calcium-binding protein parvalbumin in the zona incerta in parkinsonian rats. Sprague-Dawley rats had small volumes of either saline (control) or 6 hydroxydopamine (6OHDA) injected into the medial forebrain bundle, the major tract carrying dopaminergic nigrostriatal axons. After various post-lesion survival periods, ranging from 2 hrs to 84 days, rats were perfused with formaldehyde and their brains processed for routine tyrosine hydroxylase (TH) or parvalbumin immunocytochemistry. In the 3 to 84 days post-lesion cases, there was an overall 50% reduction in the number of parvalbumin(+) cells in the zona incerta on the 6OHDA-lesioned side when compared to control. In the 2 hrs post-lesion cases, there was no substantial loss of parvalbumin(+) cells in the zona incerta after 6OHDA lesion, although in these cases (unlike the longer survival periods), there was limited loss of TH(+) cells in the midbrain on the lesion side. The loss of parvalbumin(+) cells from the zona incerta was due to a loss of antigen expression rather than a loss of the cells themselves, since the number of Nissl-stained cells in the zona incerta was similar on the control and 6OHDA-lesioned sides. In summary, our results indicate that a loss of the midbrain dopaminergic cells induces a major change in parvalbumin expression within the zona incerta. This change may have key functional and clinical implications.
authors.affiliation: Department of Anatomy & Histology, University of Sydney, Australia.
authors.forename: Claire E
authors.initials: CE
authors.lastname: Heise
authors.forename: John
authors.initials: J
authors.lastname: Mitrofanis
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002452:Cell Count; D004195:Disease Models, Animal; D004298:Dopamine / Q000378:metabolism; D015536:Down-Regulation / Q000502:physiology; D007150:Immunohistochemistry; D008297:Male; D009434:Neural Pathways / Q000473:pathology / Q000503:physiopathology*; D009474:Neurons / Q000378:metabolism* / Q000473:pathology; D016627:Oxidopamine; D020734:Parkinsonian Disorders / Q000378:metabolism* / Q000503:physiopathology; D010320:Parvalbumins / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013378:Substantia Nigra / Q000473:pathology / Q000503:physiopathology*; D020530:Subthalamus / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D013565:Sympatholytics; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
chemical_list: D015415:Biomarkers; D010320:Parvalbumins; D013565:Sympatholytics; D016627:Oxidopamine; D014446:Tyrosine 3-Monooxygenase; D002118:Calcium; D004298:Dopamine