Correlative ontogenetic development of catecholamine- and LHRH-containing nerve endings in the median eminence of the rat

Ibata, Yasuhiko; Tani, Naoki; Obata, Hiroko; Tanaka, Masaki; Kubo, Seiichi; Fukui, Kenji; Fujimoto, Masahito; Kinoshita, H.; Watanabe, Kenji; Sano, Yutaka; Hashimura, E.; Sin, S.; Imagawa, Kenichi

doi:10.1007/bf00234542

Cited by 12 publications

(2 citation statements)

References 14 publications

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“…The exact chemical nature of these vesicles in the hamster is not known at this time. However, catecholamines have been detected as early as day 7 of the neonatal rat (Ibata et al, 1981) and day 18 of the mouse (Golden, 1973). Im- A structure similar to a growth cone (arrow) contained clear and diaphanous vesicles.…”

Section: Discussionmentioning

confidence: 99%

Morphological changes in the hypothalamic arcuate nucleus and median eminence in the golden hamster during the neonatal period

Lamperti

Mastovich

1983

Am. J. Anat.

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The purpose of the present investigation was to study the ultrastructure of the arcuate nucleus (ARC) and median eminence of hamsters on days 1-15 of the neonatal period. From days 1-6, the neurons of the ARC had large nuclei and a small amount of cytoplasm which contained polysomes, mitochondria, RER, lysosomes and Golgi complexes. From days 7-15 there was an increase in the amount of cytoplasm as well as more extensive Golgi complexes and RER. Astrocytes were the predominant glial component in both the ARC and median eminence. Astrocytic processes were in juxtaposition to unmyelinated axons, dendrites, and synapses. Axodendritic and axosomatic synapses containing clear vesicles were observed in the neuropil on day 1. There was an increase in the number of dense-core vesicles in the axonal endings beginning on day 4. Concomitantly, there were increasing numbers of clear and dense-core vesicles (64-70 nm) in terminals of the external layer of the median eminence, whereas larger dense-core vesicles (105-140 nm) were distinguishable by day 10 immediately dorsal to the external layer. The capillaries of the median eminence were composed of nonfenestrated endothelium from days 1-9. Fenestrae began to appear about day 10. Ependymal cells lining the third ventricle had pinocytotic vesicles, microvilli, and bleb-like protrusions on their apical surfaces. Ependymal processes were adjacent to nerve processes in the neuropil of the ARC and in the external layer of the median eminence, where they contacted the perivascular space. Two types of supraependymal cells were seen in animals throughout the neonatal period. One resembled a neuron which sent processes along the ependymal surface and often between cells. The second type was similar to a macrophage. The results of this study demonstrate the maturation of the neural elements in the ARC/median eminence area of the neonatal hamster.

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Section: Discussionmentioning

confidence: 99%

Morphological changes in the hypothalamic arcuate nucleus and median eminence in the golden hamster during the neonatal period

Lamperti

Mastovich

1983

Am. J. Anat.

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“…TH in ME, which are first observed at 5 -7 days o f age [25,26] and do not show the adult pattern until 14-21 days o f age [16,28]. Likewise, TH mRNA in A12 and TH syn thetic activity in ME have been reported to increase between 5 and 15 days postnatally in rats [29].…”

Section: -mentioning

confidence: 88%

Postnatal Reduction in Number of Hypothalamic Tuberoinfundibular Dopaminergic Neurons in Prolactin-Deficient Dwarf Mice

et al. 1994

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Mice homozygous for the recessive ‘Ames’ dwarf mutation have undetectable serum or pituitary prolactin (PRL). Accompanying this pituitary deficiency is a marked reduction of dopamine (DA) and its rate-limiting synthetic enzyme tyrosine hydroxylase (TH) in PRL-regulating tuberoinfundibular hypothalamic neurons. In order to determine whether this deficit in adult Ames dwarf mice is congenital or arises postnatally, brains of dwarf (df/df) and normal (DF/?) littermate mice were assessed for TH immunoreactivity from 7 days through 2 months of age. Numbers of TH-positive neurons were counted in three hypothalamic DA areas: tuberoinfundibular A12, medial zona incerta A13, and anterior periventricular A14. There was an increase in the number of TH-positive neurons between 7 and 21 days of age in A12 and A14, but not in A13, for both DF/? and df/df mice. Between 21 days and 2 months of age, cell numbers were the same in all three areas in DF/? mice and in Al 3 and A14 in df/df mice. However, A12 TH-positive cell number in dwarfs decreased significantly (p < 0.01) between 21 days and 2 months, and was markedly lower (p < 0.001) in df/df than in DF/? mice at 2 months of age. The results emphasize the specificity of the dopaminergic neuron reduction in the Ames dwarf, which is restricted to the PRL-regulating tuberoinfundibular region. The data also indicate that the dwarf DA/TH deficit has an onset in late postnatal development, suggesting a response to absence of target PRL, rather than a primary hypothalamic effect of the dwarf mutation.

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Neuroendocrine Projections to the Median Eminence

Hoffman

Phelps

Khachaturian

et al. 1986

Current Topics in Neuroendocrinology

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Correlative ontogenetic development of catecholamine- and LHRH-containing nerve endings in the median eminence of the rat

Cited by 12 publications

References 14 publications

Morphological changes in the hypothalamic arcuate nucleus and median eminence in the golden hamster during the neonatal period

Morphological changes in the hypothalamic arcuate nucleus and median eminence in the golden hamster during the neonatal period

Postnatal Reduction in Number of Hypothalamic Tuberoinfundibular Dopaminergic Neurons in Prolactin-Deficient Dwarf Mice

Neuroendocrine Projections to the Median Eminence

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