title: Age-dependent changes in dopaminergic projections from the substantia nigra pars compacta to the neostriatum.
abstract: Age-dependent changes in dopaminergic (DA) innervation of the neostriatum (Str) were studied in male F344/N rats. Projections from the substantia nigra pars compacta (SNc) to the neostriatum were quantified using electrophysiological methods at age points from 6 to 24 months. The percentage of DA neurons activated antidromically by electrical stimulation (P-index) of Str increased between 18 and 24 months. Additionally, the percentage of DA neurons showing multiple antidromic latencies from striatal stimulation (M-index), which suggests axonal branching of individual DA neurons, increased significantly between 6 and 12 months and 6 and 24 months. These results suggest that DA neurons exhibit increased axonal branching in the aged brain.
authors.affiliation: Radioisotope Research Center, Nagoya University Graduate School of Medicine, Japan. ishida@med.nagoya-u.ac.jp
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Ishida
authors.forename: Yayoi
authors.initials: Y
authors.lastname: Okawa
authors.forename: Sachiko
authors.initials: S
authors.lastname: Ito
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Shirokawa
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Isobe
mesh_terms: D000344:Afferent Pathways; D000367:Age Factors; D000375:Aging / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D004298:Dopamine / Q000378:metabolism*; D004558:Electric Stimulation / Q000379:methods; D008297:Male; D017072:Neostriatum / Q000378:metabolism*; D009474:Neurons / Q000502:physiology*; D051381:Rats; D011916:Rats, Inbred F344; D011930:Reaction Time / Q000502:physiology; D013378:Substantia Nigra / Q000166:cytology* / Q000378:metabolism
chemical_list: D004298:Dopamine