Neurochemical development of the hippocampal region in the fetal rhesus monkey. II. Immunocytochemistry of peptides, calcium-binding proteins, DARPP-32, and monoamine innervation in the entorhinal cortex by the end of gestation.
Material for the study came from one 126 day-old rhesus monkey fetus and two 3 day-old neonates. The immunocytochemical detection of somatostatin, neurotensin (NT), parvalbumin, calbindin D-28K, DARPP-32 as well as tyrosine hydroxylase (TH), dopamine-beta-hydroxylase and serotonin (5-HT), was carried out on serial cryostat sections of the entorhinal cortex. The authors reported in a previous paper the precocious differentiation of the entorhinal cortex in rhesus monkey fetuses and featured the conspicuous expression of calbindin D-28K, somatostatin, neurotensin, and the monoaminergic innervation during the first half of gestation. The present study shows distinct temporal profiles of neurochemical development during the second half of gestation: the dense neuropeptidergic innervation remained a constant feature; the three aminergic systems gradually increased in density; parvalbumin, unlike calbindin D-28K, was primarily expressed during the last quarter of gestation. Three other prominent features of the last quarter of gestation are illustrated: the refinement of the modular neurochemical organization of the lamina principalis externa, the delayed chemoanatomical development of the rhinal sulcus area, and the establishment of a distinct rostrocaudal pattern of neurochemical distribution. In correspondence with the cluster-like organization of the lamina principalis externa, the authors observed in the olfactory, rostral, and intermediate fields of the neonate monkey entorhinal cortex, a particular subset of pyramidal-shaped neurons: located in layer III, they were characterized by fasciculated apical dendrites ascending between the cellular islands of the discontinuous layer II and the coexpression of calbindin D-28K and DARPP-32. Besides, most of the other chemical systems displayed a distinct, area-specific, patchy distribution, except for the homogeneously distributed noradrenergic innervation. In the olfactory and rostral fields, TH positive dopaminergic fibers accumulated on the neuronal islands of layers II-III, and parvalbumin labeled fibers on those of layer III, whereas patches of 5-HT and NT-like reactive terminals were segregated between the cellular islands, overlapping the DARPP-32/calbindin D-28 K labeled dendritic bundles. At the opposite, in the intermediate field, 5-HT positive terminals overlapped the cellular islands of layer II and thin fascicles of dopaminergic fibers ran in the inter island spaces. The somatostatin-LIR innervation was apparently too dense to reveal a patchy distribution that existed at earlier developmental stages. In the caudal field, the patchy pattern was replaced by a predominant bilaminar type of distribution of NT, 5-HT, and TH-like positive afferents.(ABSTRACT TRUNCATED AT 400 WORDS)
Berger
B
B
INSERM U106, Hôpital Salpêtrière, Paris, France.
Alvarez
C
C
D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism; D000911:Antibodies, Monoclonal / Q000276:immunology; D015306:Biogenic Monoamines / Q000276:immunology / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000276:immunology / Q000378:metabolism*; D051937:Dopamine and cAMP-Regulated Phosphoprotein 32; D005260:Female; D006624:Hippocampus / Q000166:cytology / Q000196:embryology* / Q000378:metabolism*; D007150:Immunohistochemistry; D008253:Macaca mulatta; D009419:Nerve Tissue Proteins / Q000276:immunology / Q000378:metabolism*; D009479:Neuropeptides / Q000276:immunology / Q000378:metabolism*; D010750:Phosphoproteins; D011247:Pregnancy; D009626:Terminology as Topic; D014446:Tyrosine 3-Monooxygenase / Q000276:immunology / Q000378:metabolism
D000911:Antibodies, Monoclonal; D015306:Biogenic Monoamines; D002135:Calcium-Binding Proteins; D051937:Dopamine and cAMP-Regulated Phosphoprotein 32; D009419:Nerve Tissue Proteins; D009479:Neuropeptides; D010750:Phosphoproteins; D014446:Tyrosine 3-Monooxygenase