Catecholaminergic innervation of the hippocampus in the cynomolgus monkey.
We studied the immunocytochemical distribution of catecholaminergic fibers in the hippocampal formation from two cynomolgus monkeys by using phenylethanolamine-N-methyltransferase, dopamine-beta-hydroxylase, and tyrosine-hydroxylase antibodies. There were no phenylethanolamine-N-methyltransferase immunoreactive fibers suggesting the lack of epinephrine containing fibers. In order to compare the distributions of tyrosine-hydroxylase and dopamine-beta-hydroxylase immunoreactive fibers, we counted fibers in four hippocampal regions, the dentate gyrus, CA3, CA1, and the subiculum at three different rostrocaudal levels. The distributions of dopamine-beta-hydroxylase and tyrosine-hydroxylase immunoreactive fibers were overlapping but clearly different, suggesting that the hippocampus receives both noradrenergic and dopaminergic inputs in primates. Dopamine-beta-hydroxylase-immunoreactive fibers were present in moderate density and roughly evenly distributed throughout the hippocampus. Tyrosine-hydroxylase immunoreactive fibers were found in high density in the dentate gyrus, in the stratum lacunosum-moleculare, and in the molecular layer of the subiculum. There were only minor side-side and rostrocaudal differences in the distribution of tyrosine-hydroxylase and dopamine-beta-hydroxylase immunoreactive fibers. The identification of a putative dopaminergic projection to primate hippocampus, which is more dense and widely distributed than in the rodent, parallels similar increases in dopaminergic projections reported for primate cerebral neocortex.
Samson
Y
Y
Neurology Research Laboratory Durham V.A. Medical Center, North Carolina 27705.
Wu
J J
JJ
Friedman
A H
AH
Davis
J N
JN
D000818:Animals; D004298:Dopamine / Q000502:physiology; D004299:Dopamine beta-Hydroxylase / Q000032:analysis; D006624:Hippocampus / Q000033:anatomy & histology* / Q000166:cytology / Q000502:physiology; D007124:Immunoenzyme Techniques; D008252:Macaca fascicularis / Q000033:anatomy & histology*; D009412:Nerve Fibers / Q000201:enzymology / Q000648:ultrastructure; D009928:Organ Specificity; D011712:Pyramidal Tracts / Q000033:anatomy & histology / Q000502:physiology; D014446:Tyrosine 3-Monooxygenase / Q000032:analysis
D014446:Tyrosine 3-Monooxygenase; D004299:Dopamine beta-Hydroxylase; D004298:Dopamine