Evidence for axonal sprouting in the anterior pituitary following adrenalectomy in the rat

Lu, Chunrong; Meng, Fantao; Benowitz, Larry I.; Gao, Ju

doi:10.1677/joe.0.1470161

Cited by 19 publications

(14 citation statements)

References 17 publications

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“…Quantification of the length density of the fibres showed of CGRP-LI nerve fibres ( 10). This is due, at least in part, to no significant difference between various stages of the oestrous active axonal sprouting (11). Furthermore, electric field stimulacycle ( Fig.…”

mentioning

confidence: 88%

“…Laboratory GAP-43 immunohistochemistry has further shown that this chow and tap water were given ad libitum. The animals were allowed to increase in immunostainable nerve fibres was caused by active survive for 6 days after the operation, during which time vehicle or axonal sprouting, at least in part ( 11); and electric field stimulaoestradiol benzoate were injected subcutaneously daily following the day tion of the nerve fibres in vitro in the anterior pituitary could of the operation. enhance ACTH secretion (12).…”

Section: Institute Of Neurosciences Have Demonstrated That Nerve Fibresmentioning

confidence: 99%

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Response of Substance P‐Immunoreactive Nerve Fibres in the Anterior Pituitary to Plasma Oestrogen Levels in the Rat

Ma¹,

Zhao

Mayhew

et al. 1997

J Neuroendocrinology

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The mammalian anterior pituitary has recently been shown to be innervated by substantial amounts of peptidergic nerve fibres. It has also been found that adrenalectomy increases the amount of calcitonin gene-related peptide-like immunoreactive nerve fibres in the anterior pituitary of the rat, and that stimulation of the nerve fibres in vitro can enhance release of ACTH. In the present study, the density of substance P-like immunoreactive nerve fibres in the anterior pituitary of the rat were examined in relation to variations in plasma oestrogen status. The amount of substance P-like immunoreactive nerve fibres increased significantly (P < 0.001) after ovariectomy, and decreased significantly (P < 0.01) under oestrogen replacement, in a dose-dependent manner. The results suggest the possibility of the direct neural involvement of oestrogen secretion in anterior pituitary regulation, which further substantiates the hypothesis of neural-humoral dual regulation of the mammalian anterior pituitary.

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mentioning

confidence: 88%

Section: Institute Of Neurosciences Have Demonstrated That Nerve Fibresmentioning

confidence: 99%

Response of Substance P‐Immunoreactive Nerve Fibres in the Anterior Pituitary to Plasma Oestrogen Levels in the Rat

Ma¹,

Zhao

Mayhew

et al. 1997

J Neuroendocrinology

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“…The nerve fibers are closely related to the gland cells rather than to the blood vessels (Ju and Liu 1989b, c). Adrenalectomy in the rat caused a significant increase in the number of CGRP-LI nerve fibers ) and, concurrently, there was a marked increase of GAP-43 (growth associated protein) immunoreactivity, implying an active axonal sprouting in response to the hormonal change of the animal (Lu et al 1995). However, the discovery of synapses between the nerve fibers and gland cells in the anterior pituitary of the dog Zhang 1990, 1992) was the key significant observation for our hypothesis of neural-humoral dual regulation of the mammalian anterior pituitary.…”

Section: Introductionmentioning

confidence: 99%

Synaptic relationship of substance P-like-immunoreactive nerve fibers with gland cells of the anterior pituitary in the rat

Liu

Morris

1996

Cell and Tissue Research

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Our previous studies have proved the presence of substantial amounts of peptidergic nerve fibers in the anterior pituitary of human, monkey, dog, and rat, and synaptic contacts have been demonstrated on corticotrophs and somatotrophs in the dog. The present study is aimed at investigating the synaptic relationship between axons and gland cells in the rat. The substance P-like-immunoreactive nerve fibers were studied immuno-electron-microscopically. They were nonmyelinated and varicose. Typical synaptic contacts between the fibers and every type of the hormone-secreting gland cell could be identified, most frequently on lactotrophs. No synaptic contacts were found on the folliculo-stellate cell. The synaptic contacts were of asymmetrical type with clusters of small round clear vesicles at the presynaptic site and scattered large dense-cored vesicles. This pattern of synaptic relationships was markedly different from that in the dog. The presence of synapses in the anterior pituitary of the rat implies a direct neural regulation of certain cells and strongly supports our hypothesis of neural-humoral dual regulation of this gland.

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“…GAP-43 is a nervous systemspecific membrane protein that is related to axonal regeneration and synaptic remodelling. 21 The marked increase in GAP-43 immunoreactivity in the anterior pituitary following adrenalectomy implies that the nerve fibres can respond to changes in hormone levels by active axonal sprouting, 22 apparently indicating a significant role the nerve fibres may be playing.…”

Section: Are the Nerve Fibres Functionally Important Or Are They Redumentioning

confidence: 99%

Evidence for Direct Neural Regulation of the Mammalian Anterior Pituitary

1999

Clin Exp Pharma Physio

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1. The mammalian anterior pituitary was not known to be directly regulated by nervous elements until recently. Although it is generally acknowledged that there are a small number of nerve fibres in the anterior pituitary, they are considered to be autonomic in nature and are not directly involved in the regulation of the activities of the gland cells. 2. A growing body of evidence has been accumulated in the past decade, mainly from our laboratory, indicating that the anterior pituitary can be directly regulated by nerve fibres innervating it. The present article reviews the evidence for the hypothesis that there is neural-humoral dual regulation of the mammalian anterior pituitary. 3. Human, macaque monkey, dog and rat anterior pituitaries have been used for immunocytochemical studies at light and electron microscopic levels. Studies of the changes in the nerve fibres in the anterior pituitary following adrenalectomy or ovariectomy have been conducted on rats. The effects of electrical stimulation of the nerve fibres in the anterior pituitary on adrenocorticotropic hormone (ACTH) secretion have also been studied. 4. There are substantial amounts of nerve fibres in the anterior pituitary. They are in close proximity to the gland cells, including forming synapses. The number of nerve terminals are large. Adrenalectomy or ovariectomy induces an active response of the nerve fibres and electrical stimulation of the nerve fibres changes ACTH secretion. 5. It has been concluded that the anterior pituitary can be directly regulated by the innervating nerve fibres.

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Evidence for axonal sprouting in the anterior pituitary following adrenalectomy in the rat

Cited by 19 publications

References 17 publications

Response of Substance P‐Immunoreactive Nerve Fibres in the Anterior Pituitary to Plasma Oestrogen Levels in the Rat

Response of Substance P‐Immunoreactive Nerve Fibres in the Anterior Pituitary to Plasma Oestrogen Levels in the Rat

Synaptic relationship of substance P-like-immunoreactive nerve fibers with gland cells of the anterior pituitary in the rat

Evidence for Direct Neural Regulation of the Mammalian Anterior Pituitary

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