An immunocytochemical study of a G-protein-gated inward rectifier K+ channel (GIRK2) in the weaver mouse mesencephalon.
It has been suggested that a mutation in a G-protein-gated inward rectifier K+ channel (GIRK2) is responsible for inducing cell death in the cerebellum of homozygous weaver (wv/wv) mutant mice. These mice also display a progressive, massive loss of mesencephalic dopaminergic neurones. Using an immunocytochemical method, we detected GIRK2-positive cell bodies and fibres in the substantia nigra pars compacta (SNC) and the ventral tegmental area (VTA) of control (+/+) mice. Cell counts of both GIRK2- and tyrosine hydroxylase (TH)-positive neurones demonstrated a marked loss of SNC cell bodies, especially in 12-month-old (12M) wv/wv mice. A considerable proportion of GIRK2-positive cell bodies were preserved, however. In addition, no loss of GIRK2-positive neurones was observed in the VTA of 12M wv/wv mice, despite of a significant reduction in TH-positive cell bodies. These results suggest that expression of the mutated channel is not a sufficient condition to induce cell death in the ventral mesencephalon of the wv/wv mice.
Adelbrecht
C
C
INSERM U289, Hôpital de la Sâlpêtrière, Paris.
Murer
M G
MG
Lauritzen
I
I
Lesage
F
F
Ladzunski
M
M
Agid
Y
Y
Raisman-Vozari
R
R
D000375:Aging / Q000502:physiology; D000818:Animals; D015415:Biomarkers; D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; D019204:GTP-Binding Proteins / Q000032:analysis; D007150:Immunohistochemistry; D008297:Male; D008636:Mesencephalon / Q000166:cytology* / Q000254:growth & development; D051379:Mice; D008818:Mice, Neurologic Mutants; D009412:Nerve Fibers / Q000648:ultrastructure; D009474:Neurons / Q000166:cytology*; D015221:Potassium Channels / Q000032:analysis*; D024661:Potassium Channels, Inwardly Rectifying; D012016:Reference Values; D013378:Substantia Nigra / Q000166:cytology / Q000254:growth & development; D013681:Tegmentum Mesencephali / Q000166:cytology / Q000254:growth & development; D014446:Tyrosine 3-Monooxygenase / Q000032:analysis
D015415:Biomarkers; D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D014446:Tyrosine 3-Monooxygenase; D019204:GTP-Binding Proteins