TY - JOUR
T1 - Morphological impairments in retinal neurons of the scotopic visual pathway in a monkey model of Parkinson's disease
AU - Cuenca, Nicolás
AU - Herrero, María Trinidad
AU - Angulo, Antonia
AU - De Juan, Emilio
AU - Martínez-Navarrete, Gema C.
AU - López, Salvador
AU - Barcia, Carlos
AU - Martín-Nieto, José
PY - 2005/12/12
Y1 - 2005/12/12
N2 - Physiological abnormalities resulting from death of dopaminergic neurons of the central nervous system in Parkinson's disease also extend to the retina, resulting in impaired visual functions. In both parkinsonian patients and animal models, low levels of dopamine and loss of dopaminergic cells in the retina have been reported. However, the morphology and connectivity of their postsynaptic neurons, the amacrine cells, have not been analyzed. Here we report, with macaques chronically treated with 1-methyl-4-phenyl-1,2,3,6- tetrahydropyridine (MPTP) as a model of Parkinson's disease, that morphological impairments in dopaminergic retinal neurons and their plexus in the inner retina are accompanied by an immunoreactivity decrease in γ-aminobutyric acidergic and glycinergic amacrine cells. Especially deteriorated were AII amacrine cells, the main neuronal subtype postsynaptic to dopaminergic cells, which exhibited a marked loss of lobular appendages and dendritic processes. Concomitantly, electrical synapses among AII cells, as well as chemical synapses between these and rod bipolar cells, were highly deteriorated in parkinsonian monkeys. These results highlight that the scotopic visual pathway is severely impaired in the parkinsonian condition and provide a morphological basis for a number of abnormalities found in electrophysiological and psychophysical trials in Parkinson's disease patients and animal models.
AB - Physiological abnormalities resulting from death of dopaminergic neurons of the central nervous system in Parkinson's disease also extend to the retina, resulting in impaired visual functions. In both parkinsonian patients and animal models, low levels of dopamine and loss of dopaminergic cells in the retina have been reported. However, the morphology and connectivity of their postsynaptic neurons, the amacrine cells, have not been analyzed. Here we report, with macaques chronically treated with 1-methyl-4-phenyl-1,2,3,6- tetrahydropyridine (MPTP) as a model of Parkinson's disease, that morphological impairments in dopaminergic retinal neurons and their plexus in the inner retina are accompanied by an immunoreactivity decrease in γ-aminobutyric acidergic and glycinergic amacrine cells. Especially deteriorated were AII amacrine cells, the main neuronal subtype postsynaptic to dopaminergic cells, which exhibited a marked loss of lobular appendages and dendritic processes. Concomitantly, electrical synapses among AII cells, as well as chemical synapses between these and rod bipolar cells, were highly deteriorated in parkinsonian monkeys. These results highlight that the scotopic visual pathway is severely impaired in the parkinsonian condition and provide a morphological basis for a number of abnormalities found in electrophysiological and psychophysical trials in Parkinson's disease patients and animal models.
KW - AII amacrines
KW - Connexin-36
KW - Dopaminergic neurons
KW - Parkinsonian monkeys
KW - Retina
UR - http://www.scopus.com/inward/record.url?scp=27944469068&partnerID=8YFLogxK
U2 - 10.1002/cne.20761
DO - 10.1002/cne.20761
M3 - Article
C2 - 16255027
AN - SCOPUS:27944469068
SN - 0021-9967
VL - 493
SP - 261
EP - 273
JO - Journal of Comparative Neurology
JF - Journal of Comparative Neurology
IS - 2
ER -