The crossed mesostriatal projection: neurochemistry and developmental response to lesion.
The projections of substantia nigra and ventral tegmental area (SN-VTA) neurons to either the ipsilateral or contralateral caudate-putamen (CP) were studied in intact and 6-hydroxydopamine-treated rats, using both retrograde transport of fluorescent dyes and measurements of dopamine concentration. After unilateral CP injections of nuclear yellow or granular blue in intact 6- or 30-day-old rats, approximately 1% of the retrogradely labeled cells were located in the contralateral SN-VTA. In 6- or 30-day-old rats which had been injected with 6-hydroxydopamine in the left lateral hypothalamic area (LHA) at 1 day of age, the extent of cell labeling of both the uncrossed projection in the right hemisphere and the crossed projection originating in the left SN-VTA was normal. However, the number of labeled cells of the uncrossed pathway of the left side and the crossed pathway originating in the right SN-VTA were markedly decreased by the lesion, indicating that the crossed nigrostriatal cells decussate before they reach the LHA. The 6-hydroxydopamine-induced decreases in SN-VTA labeling of both the crossed and uncrossed pathway closely matched the degree of dopamine depletion in the lesioned CP at 6 days of age and at 30 days of age. A partial recovery of both measures occurred between days 6 and 30. Thus, retrograde labeling of SN-VTA cells and at 30 days of age. A partial recovery of both measures occurred between days 6 and 30. Thus, retrograde labeling of SN-VTA cells with fluorescent dyes provided a quantitative measure of the dopaminergic innervation of the neostriatum in both the uncrossed and crossed pathways.(ABSTRACT TRUNCATED AT 250 WORDS)
D000818:Animals; D002421:Caudate Nucleus / Q000033:anatomy & histology; D003342:Corpus Striatum / Q000033:anatomy & histology* / Q000187:drug effects; D004292:Dominance, Cerebral / Q000502:physiology*; D004298:Dopamine / Q000378:metabolism*; D006892:Hydroxydopamines / Q000494:pharmacology; D008297:Male; D008636:Mesencephalon / Q000033:anatomy & histology* / Q000187:drug effects; D009416:Nerve Regeneration; D009434:Neural Pathways / Q000033:anatomy & histology / Q000187:drug effects; D009474:Neurons / Q000648:ultrastructure; D016627:Oxidopamine; D011699:Putamen / Q000033:anatomy & histology; D051381:Rats; D011919:Rats, Inbred Strains; D013378:Substantia Nigra / Q000033:anatomy & histology; D013681:Tegmentum Mesencephali / Q000033:anatomy & histology
D006892:Hydroxydopamines; D016627:Oxidopamine; D004298:Dopamine