Changes in Corticotrophin Releasing Factor of the Stalk Median Eminence in Rats With Various Cuts Around the Medial Basal Hypothalamus

Makara, Gábor B.; Stark, E.; Rappay, G; Kárteszi, M.; Palkovits, Miklós

doi:10.1677/joe.0.0830165

Cited by 45 publications

(26 citation statements)

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“…The present results -which show remarkable similarity to data on the origin of CRF in the stalk-median eminence region [21,23] -allow some speculations on the possible origin of CRF-containing structures of the NL.…”

Section: Discussionsupporting

confidence: 88%

“…In rats with carefully checked anterolateral cuts around the MBH there was no activation of the pituitaryadrenal system following such stimuli as electrical stimula- , and ether inhalation [16,22]. The CRF activity of the stalk and median eminence region decreased to less than 1 / 10th of the controls [23]. All this evidence suggests thatcontrary to earlier views -CRF in the neurohemal areas of the hypothalamopituitary unit may originate from out side of the MBH.…”

mentioning

confidence: 64%

“…Neural lobes were freed of intermediate lobe cell clumps, ex tracted and their CRF activity was tested on a miniaturized system using monolayer cultures of anterior pituitary cells and ACTH radio immunoassay as described [17,23]. Additional assays were performed using the intrapituitary microinjection method of Hiroshige et a!.…”

Section: Bioassay O F Crf Activitymentioning

confidence: 99%

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Effect of Electrical Stimulation of the Neurohypophysis on ACTH Release in Rats with Hypothalamic Lesions

et al. 1980

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Electrical stimulation of the neural lobe (NL) of the pituitary induces a rise in plasma corticosterone indicating the release of adrenocorticotropin (ACTH) in rats pretreated with dexamethasone, morphine and pentobarbitone. 7–8 days after placing an anterolateral cut around the medial basal hypothalamus (MBH), the rats failed to respond with ACTH release to electrical stimulation of the NL; the number of nerve fibers and terminals in the NL decreased to less than 5% of the normal; and ACTH releasing activity of acid extracts of the NL was undetectable using both in vivo and in vitro tests, which are insensitive to vasopressin. After lesions of the paraventricular nuclei the stimulation of the NL elicited a rise of plasma corticosterone that was significantly less than that in the controls. These results suggest that the NL of the pituitary contains electrically excitable fibers capable of releasing corticotropin-releasing factor (CRF; distinct from vasopressin) and that these fibers probably originate from outside the MBH, witha portion of them coming from or through the paraventricular nuclei or their immediate vicinity.

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Section: Discussionsupporting

confidence: 88%

mentioning

confidence: 64%

Section: Bioassay O F Crf Activitymentioning

confidence: 99%

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Effect of Electrical Stimulation of the Neurohypophysis on ACTH Release in Rats with Hypothalamic Lesions

et al. 1980

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“…It seems unlikely that in both cases 5-HT receptor supersensitivity would be induced to the same extent such that it could compensate for the reduction of serotonin content in those hypothalamic areas which are in the vicinity of the CRF producing cells [11,19,Makara et al,in preparation]. However, further experiments are needed to strengthen this view.…”

Section: Discussionmentioning

confidence: 98%

Lack of Correlation between Hypothalamic Serotonin and the Ether-Induced ACTH Secretion in Adrenalectomized Rats

et al. 1981

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The central serotonergic system was manipulated using a serotonin receptor antagonist (cyproheptadine), electrolytic lesioning of the raphe nuclei and neurochemical destruction of the serotonergic terminals in the hypothalamus. The effects of these interventions on ether-induced ACTH secretion were studied in adrenalectomized rats. Serotonin, norepinephrine and dopamine concentrations were measured in the medial basal hypothalamus (MBH) or in individual nuclei of the hypothalamus and of certain midbrain regions. Cyproheptadine pretreatment inhibited ether-induced ACTH hypersecretion in adrenalectomized animals. Neither the electrolytic lesions of the midbrain raphe nuclei, nor the neurotoxic destruction of the hypothalamic serotonergic terminals (by intraventricular administration of 5,6-dihydroxytryptamine) caused any alteration of stimulated ACTH secretion after ether inhalation and/or long-term corticoid deficiency. These results suggest a lack of correlation between the activity of the central serotonergic system and the ACTH releasing effect of ether stress in adrenalectomized rats.

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“…Other experimental models of central DI have been created, some of them based on pituitary stalk transsection (Pu et al 1995, Huang & Dellmann 1996. However, this surgical procedure induces not only central DI but also anterior pituitary failure (Makara et al 1979), therefore studies involving the activity of the HPA axis cannot be performed. To overcome this difficulty, the pituitary stalk compression model of central DI has been used (Dohanics et al 1992, Makara 1993.…”

Section: Discussionmentioning

confidence: 99%

Hypothalamic-pituitary-adrenal axis up-regulation in rats submitted to pituitary stalk compression

Elias¹,

Elias²,

Castro³

et al. 2004

Journal of Endocrinology

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The present study investigated the hypothalamicpituitary-adrenal (HPA) axis activity in response to stress in adult male rats submitted to pituitary stalk compression (PSC) or sham operation. Animals received water or oral salt loading (2% NaCl) for one or eight days before the day of the experiment. On the 14th day post-surgery rats were killed under basal conditions or after 15 min immobilization stress. In the PSC group urine output increased significantly and plasma vasopressin (AVP) levels failed to respond to osmotic stimuli. Short-term salt load induced a significant increase in AVP levels in the sham-operated group. The PSC group presented higher adrenocorticotrophin (ACTH) and corticosterone levels compared with sham-operated rats, both in water intake and salt load conditions. Immobilization stress induced a similar increase in plasma ACTH and corticosterone concentrations in sham-operated and PSC groups under water intake. However, long-term salt load blunted the ACTH and corticosterone responses to immobilization stress in sham-operated rats. PSC rats submitted to short-and long-term salt loading presented no changes in ACTH and corticosterone levels after immobilization. Immobilization stress caused neither AVP responses nor plasma osmolality changes in sham and PSC groups. There was no difference in median eminence AVP content among all groups. In conclusion, the high ACTH and corticosterone levels found in PSC rats under water intake and salt loading conditions suggest an up-regulation of the HPA axis, with a preserved adaptive mechanism to chronic stress.

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Changes in Corticotrophin Releasing Factor of the Stalk Median Eminence in Rats With Various Cuts Around the Medial Basal Hypothalamus

Cited by 45 publications

References 0 publications

Effect of Electrical Stimulation of the Neurohypophysis on ACTH Release in Rats with Hypothalamic Lesions

Effect of Electrical Stimulation of the Neurohypophysis on ACTH Release in Rats with Hypothalamic Lesions

Lack of Correlation between Hypothalamic Serotonin and the Ether-Induced ACTH Secretion in Adrenalectomized Rats

Hypothalamic-pituitary-adrenal axis up-regulation in rats submitted to pituitary stalk compression

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