Lesions of hypothalamic PVN partially attenuate stimulatory action of alcohol on ACTH secretion in rats

1994 ◽  
Vol 266 (2) ◽  
pp. R553-R558 ◽  
Author(s):  
S. Rivest ◽  
C. Rivier
Keyword(s):  
Brain Regions ◽  
Acute Administration ◽  
Mrna Levels ◽  
Acth Secretion ◽  
Stimulatory Action ◽  
Acute Injection ◽  
Bilateral Lesions ◽  
Acth Release

We have previously shown that the ability of alcohol to stimulate adrenocorticotropic hormone (ACTH) secretion was significantly blunted by immunoneutralization of endogenous corticotropin-releasing factor (CRF) and that long-term exposure to alcohol increased CRF mRNA levels in the paraventricular nucleus (PVN) of the hypothalamus. In the present study, we further investigated the participating role of the PVN by studying the effect of bilateral lesions of the PVN on alcohol-induced ACTH release. The acute injection of alcohol (1.5 g/kg ip) induced significant increases in plasma ACTH levels in sham-operated animals. Lesions of the PVN attenuated this response but did not abolish it. Indeed, lesioned rats retained significantly elevated ACTH values despite removal of secretagogues of PVN origin. Because removal of hypothalamic CRF can alter ACTH secretion in response to secretagogues, we studied possible changes in pituitary responsiveness to CRF. The results failed to indicate that hyperresponsiveness of the corticotrophs played a major role in accounting for the residual ACTH release of lesioned rats after alcohol treatment. We conclude that brain regions other than the PVN can modulate ACTH release during acute administration of alcohol.

scholarly journals Hypothalamic-pituitary-adrenal activity and pro-opiomelanocortin mRNA levels in the hypothalamus and pituitary of the rat are differentially modulated by acute intermittent morphine with or without water restriction stress

1999 ◽  
Vol 163 (2) ◽  
pp. 261-267 ◽  
Author(s):  
Y Zhou ◽  
R Spangler ◽  
CE Maggos ◽  
XM Wang ◽  
JS Han ◽  
...  
Keyword(s):  
Anterior Pituitary ◽  
Plasma Corticosterone ◽  
Acute Administration ◽  
Mrna Levels ◽  
Water Restriction ◽  
Plasma Acth ◽  
Acth Secretion ◽  
Hypothalamic Pituitary Adrenal ◽  
Pomc Mrna

Acute administration of morphine stimulates the secretion of hypothalamic-pituitary-adrenal (HPA) hormones, ACTH, beta-endorphin and corticosterone in the rat. In this study we investigated the effects of repeated multiple-dose morphine on HPA activity under two different conditions: without or with water restriction stress. Rats received six intermittent injections of morphine (6.25 mg/kg per injection, s.c.) every 2 h and were killed 30 min after the last injection. The results were as follows. (1) Morphine significantly elevated plasma ACTH and corticosterone levels; water restriction also significantly increased ACTH secretion, but with no significant increase of plasma corticosterone levels. In contrast, rats treated with morphine under the water restriction condition failed to show any increases of either ACTH or corticosterone levels. (2) Morphine did not change pro-opiomelanocortin (POMC) mRNA levels in the anterior pituitary; whereas water restriction significantly increased the POMC mRNA levels. The water restriction-induced increases of POMC mRNA in the anterior pituitary were absent in the rats which received morphine. (3) Morphine significantly increased POMC mRNA levels in the hypothalamus; water restriction had no effect. The morphine-induced increases in POMC mRNA in the hypothalamus were absent in the rat under the water restriction condition. These findings, that the effects of morphine on HPA activation or POMC mRNA expression depend on the presence of stress, suggest a counter-regulatory role of opiates on a stress response and opioid gene expression.

Non-pituitary actions of somatostatin. A review on the therapeutic role of SMS 201-995 (sandostatin)

1986 ◽  
Vol 113 (2_Suppla) ◽  
pp. S41-S55 ◽  
Author(s):  
Steven W. J. Lamberts
Keyword(s):  
Half Life ◽  
Potential Role ◽  
Somatostatin Analogs ◽  
Subcutaneous Administration ◽  
Term Treatment ◽  
Acute Administration ◽  
Intestinal Function ◽  
Long Term Treatment

Abstract. Natural Somatostatin has a short half-life (3 min), is only active after intravenous administration and causes a rebound hypersecretion of hormones after discontinuation of administration. Recently a longacting powerful Somatostatin analog was developed (SMS 201-995; Sandostatin) which has a half-life of 113 min after subcutaneous administration. After administration of this analog no rebound hypersecretion of hormones was observed. In the present review the effects of the acute administration and of long-term treatment with SMS 201-995 in acromegalic patients is discussed. In addition the potential role of therapy with Somatostatin analogs and the preliminary effects of Somatostatin and/or SMS 201-995 are discussed in disorders of gastro-intestinal function (haemorrhages, diarrhoea, pancreatitis and endocrine pancreatic tumours), diabetes mellitus, central nervous system disturbances and oncology. Finally, several aspects of the tolerance, tachyphylaxis and side effects of SMS 201-995 are discussed.

Adult Neurogenesis in the Songbird: Region-Specific Contributions of New Neurons to Behavioral Plasticity and Stability

2016 ◽  
Vol 87 (3) ◽  
pp. 191-204 ◽  
Author(s):  
Carolyn L. Pytte
Keyword(s):  
Behavioral Plasticity ◽  
Brain Regions ◽  
Long Term Storage ◽  
Behavioral Stability ◽  
New Information ◽  
Neuron Function ◽  
Motor Production ◽  
Term Storage

Our understanding of the role of new neurons in learning and encoding new information has been largely based on studies of new neurons in the mammalian dentate gyrus and olfactory bulb - brain regions that may be specialized for learning. Thus the role of new neurons in regions that serve other functions has yet to be fully explored. The song system provides a model for studying new neuron function in brain regions that contribute differently to song learning, song auditory discrimination, and song motor production. These regions subserve learning as well as long-term storage of previously learned information. This review examines the differences between learning-based and activity-based retention of new neurons and explores the potential contributions of new neurons to behavioral stability in the song motor production pathway.

Evidence for the Role of Endogenous Carbon Monoxide in Memory Processing

2007 ◽  
Vol 19 (4) ◽  
pp. 557-562 ◽  
Author(s):  
M. C. Cutajar ◽  
T. M. Edwards
Keyword(s):  
Carbon Monoxide ◽  
Long Term Potentiation ◽  
Brain Regions ◽  
Memory Research ◽  
Memory Processing ◽  
Important Target ◽  
Term Potentiation ◽  
Per Se

For a decade and a half, nitric oxide (NO) has been implicated in memory processing across a wide variety of tasks and species. Comparatively, endogenously produced carbon monoxide (CO) has lagged behind as a target for research into the pharmacological processes underlying memory formation. This is surprising given that CO is formed in memory-associated brain regions, is structurally similar to NO, and along with NO can activate guanylate cyclase, which is an enzyme well characterized in memory processing. Nevertheless, a limited number of electrophysiological investigations have concluded that endogenous CO is involved in long-term potentiation. Although not evidence for a role in memory per se, these studies did point to the possible importance of CO in memory processing. In addition, there is now evidence to suggest that endogenous CO is important in avoidance learning and possible for other tasks. This review therefore seeks to promote endogenous CO as a potentially important target for memory research.

Cellular localization of apelin and its receptor in the anterior pituitary: evidence for a direct stimulatory action of apelin on ACTH release

2007 ◽  
Vol 292 (1) ◽  
pp. E7-E15 ◽  
Author(s):  
Annabelle Reaux-Le Goazigo ◽  
Rodrigo Alvear-Perez ◽  
Philippe Zizzari ◽  
Jacques Epelbaum ◽  
Marie-Thérèse Bluet-Pajot ◽  
...  
Keyword(s):  
Anterior Pituitary ◽  
Cellular Localization ◽  
Physiological Role ◽  
Nerve Fibers ◽  
Male Rat ◽  
Stimulatory Action ◽  
Receptor Mrna ◽  
Apelin Receptor ◽  
Acth Release

Apelin is a bioactive peptide recently identified as the endogenous ligand of the human orphan G protein-coupled receptor APJ. The presence of apelin-immunoreactive nerve fibers, together with the detection of apelin receptor mRNA in the parvocellular part of the paraventricular nucleus and the stimulatory action of apelin on corticotropin-releasing hormone release, indicate that apelin modulates adrenocorticotropin (ACTH) release via an indirect action on the hypothalamus. However, a direct action of apelin in the anterior pituitary cannot be excluded. Here, we provided evidence for the existence of an apelinergic system within the adult male rat pituitary gland. Double immunofluorescence staining indicated that apelin is highly coexpressed in the anterior pituitary, mainly in corticotrophs (96.5 ± 0.3%) and to a much lower extent in somatotropes (3.2 ± 0.2%). Using in situ hybridization combined with immunohistochemistry, a high expression of apelin receptor mRNA was also found in corticotrophs, suggesting a local interaction between apelin and ACTH. In an ex vivo perifusion system of anterior pituitaries, apelin 17 (K17F, 10−6 M) significantly increased basal ACTH release by 41%, whereas apelin 10 (R10F, 10−6 M), an inactive apelin fragment, was ineffective. In addition, K17F but not R10F induced a dose-dependent increase in K+-evoked ACTH release, with maximal increase being observed for a 10−6 M concentration. Taken together, these data outline the potential role of apelin as an autocrine/paracrine-acting peptide on ACTH release and provide morphological and neuroendocrine basis for further studies that explore the physiological role of apelin in the regulation of anterior pituitary functions.

scholarly journals Amyloid-β Processing in Aged S100B Transgenic Mice Is Sex Dependent

2021 ◽  
Vol 22 (19) ◽  
pp. 10823
Author(s):  
Krista Minéia Wartchow ◽  
Leticia Rodrigues ◽  
Izabela Swierzy ◽  
Michael Buchfelder ◽  
Diogo Onofre de Souza ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Calcium Binding ◽  
Behavioral Responses ◽  
Amyloid Β ◽  
Brain Regions ◽  
Wild Type ◽  
One Year ◽  
Protein S100b

(1) Background: Calcium-binding protein S100B is involved in neuroregeneration but has also been associated with neurodegeneration. These contrasting effects may result from concentration or duration of exposure. We investigated the effect of long-term increased S100B levels on amyloid-β processing in one-year-old transgenic (tg) mice with 12 copies of the murine S100B gene with specific consideration of sex and specific brain regions. (2) Methods: S100B and amyloid-β 42 (Aβ42) were quantified in serum, cerebrospinal fluid (CSF), adipose tissue, and different brain regions by ELISA in wild-type (wt) and S100Btg mice (each n = 7 per group). Thioflavin T (ThT) and Aβ immunostaining were performed for visualization of Aβ deposition. (3) Results: S100B in serum, CSF, and brain was significantly increased in S100Btg mice of both sexes. Aβ42 was significantly increased in the hippocampus of male S100Btg mice (p = 0.0075), and the frontal cortex of female S100Btg mice (p = 0.0262). ThT and Aβ immunostaining demonstrated Aβ deposition in different brain regions in S100Btg mice of both sexes and female wt. (4) Conclusion: Our data validate this experimental model for studying the role of S100B in neurodegeneration and indicate that Aβ processing is sex-dependent and brain region-specific, which deserves further investigation of signaling pathways and behavioral responses.

scholarly journals Biological Predictors of De Novo Tumors in Solid Organ Transplanted Patients During Oncological Surveillance: Potential Role of Circulating TERT mRNA

2021 ◽  
Vol 11 ◽  
Author(s):  
Michela Cangemi ◽  
Stefania Zanussi ◽  
Enrica Rampazzo ◽  
Ettore Bidoli ◽  
Silvia Giunco ◽  
...  
Keyword(s):  
Peripheral Blood ◽  
De Novo ◽  
Solid Organ Transplantation ◽  
Solid Organ ◽  
Mrna Levels ◽  
Blood Samples ◽  
Tumor Onset ◽  
Diagnosis Of Cancer

BackgroundDe novo tumors are a major cause of morbidity and mortality after long-term solid organ transplantation. Chronic immunosuppression strongly affects solid organ transplanted (SOT) patients’ immune system by promoting immune evasion strategies and reactivations of viruses with oncogenic potential, ultimately leading to cancer onset. In this scenario, an oncological Surveillance Protocol integrated with biobanking of peripheral blood samples and evaluation of immunovirological and molecular parameters was activated for SOT patients at CRO-IRCCS Aviano, with the aim of identifying suitable biomarkers of cancer development.MethodsAn exploratory longitudinal study was designed based on two serial peripheral blood samples collected at least three months apart. Forty nine SOT patients were selected and stratified by tumor onset during follow-up. Spontaneous T-cell responses to EBV, CMV and tumor associated antigens, EBV-DNA and CMV-DNA loads, and circulating TERT mRNA levels were investigated.ResultsSignificantly higher levels of circulating TERT mRNA were observed 3.5-23.5 months before and close to the diagnosis of cancer as compared to tumor-free patients. Plasmatic TERT mRNA levels >97.73 copies/mL at baseline were significantly associated with the risk of developing de novo tumors (HR=4.0, 95%C.I. = 1.4-11.5, p=0.01). In particular, the risk significantly increased by 4% with every ten-unit increment in TERT mRNA (HR=1.04, 95%C.I. = 1.01-1.07, p=0.01).ConclusionsAlthough obtained in an exploratory study, our data support the importance of identifying early biomarkers of tumor onset in SOT patients useful to modulate the pace of surveillance visits.

Roles of CREB Signaling Pathway in Regulation of Fear Memory

2009 ◽  
Vol 24 (S1) ◽  
pp. 1-1
Author(s):  
S. Kida
Keyword(s):  
Gene Expression ◽  
Gene Expression Regulation ◽  
Fear Memory ◽  
Brain Regions ◽  
Contextual Fear ◽  
Contextual Fear Memory ◽  
New Gene ◽  
Activity Dependent

Activity-dependent gene expression through activation of Ca2+-CREB signal transduction pathways has been thought to play a central role in fear memory formation. On the other hand, retrieval of fear memory triggers two time-dependent phases of reactivated memory; reconsolidation and extinction. To understand the mechanisms for determining the fate of the reactivated fear memory, we investigated roles of CREB in reconsolidation and extinction of contextual fear memory and then analyzed the brain-regions regulating reconsolidation and extinction by identifying regions where CREB-mediated gene expression is activated and then examining the role of protein synthesis in those regions on reconsolidation and extinction. We first showed that activation of CREB-mediated transcription is required for reconsolidation and long-term extinction of contextual fear memory. Using immunocytochemical analyses, we demonstrated that CREB is activated in the hippocampus/amygdala and amygdala/medial prefrontal cortex (mPFC) in the reconsolidation and extinction phases, respectively. Similar results were observed by analyzing the expression of a CREB-dependent gene, Arc. We finally showed that reconsolidation and long-term extinction of the contextual fear memory depended on new gene expression in the hippocampus/amygdala and amygdala/mPFC, respectively. Thus reactivated contextual fear memory is reconsolidated or extinguished through distinct CREB-mediated gene expression regulation in the hippocampus, amygdala and mPFC.

Stress Aggravates High-Fat-Diet-Induced Insulin Resistance via a Mechanism That Involves the Amygdala and Is Associated with Changes in Neuroplasticity

2018 ◽  
Vol 107 (2) ◽  
pp. 147-157 ◽  
Author(s):  
Sheng-Feng Tsai ◽  
Hung-Tsung Wu ◽  
Pei-Chun Chen ◽  
Yun-Wen Chen ◽  
Megan Yu ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
High Fat Diet ◽  
Tissue Expansion ◽  
Plasma Corticosterone ◽  
High Fat ◽  
Obesity In Mice ◽  
Bilateral Lesions

Background: The notion that exposure to chronic stress predisposes individuals to developing type 2 diabetes (T2D) has gained much attention in recent decades. Long-term stress induces neuroadaptation in the amygdala and increases corticosterone levels. Corticosterone, the major stress hormone in rodents, induces insulin resistance and obesity in mice. However, little is known about whether the stress-induced amygdalar neuroadaptation could promote the risk of T2D. Methods: We used an 11-week high-fat diet (HFD) feeding paradigm to induce insulin dysfunction in mice, followed by implementation of a 10-day social defeat (SD) stress protocol. Results: Mice receiving SD at the beginning of the HFD feeding aggravated HFD-induced insulin resistance and white adipose tissue expansion. HFD mice had higher levels of plasma corticosterone, which was not affected by the SD. The SD stress upregulated the expression of TrkB and synaptotagmin-4 in the amygdala of HFD mice. Bilateral lesions of the central amygdalae before SD stress inhibited the stress-induced aggravating effect without affecting the HFD-induced elevation of plasma corticosterone. Conclusions: Stress aggravates HFD-induced insulin resistance and neuroadaptation in the amygdala. The HFD-induced insulin resistance is amygdala-dependent. Understanding the role of stress-induced amygdalar adaptation in the development of T2D could inform therapies aimed at reducing chronic stressors to decrease the risk for T2D.

Differential regulation of the expression of Na+/H+ exchanger isoform NHE3 by PKC-α in Caco-2 cells

2001 ◽  
Vol 281 (5) ◽  
pp. C1551-C1558 ◽  
Author(s):  
W. A. Alrefai ◽  
B. Scaglione-Sewell ◽  
S. Tyagi ◽  
L. Wartman ◽  
T. A. Brasitus ◽  
...  
Keyword(s):  
Mrna Level ◽  
Cell Types ◽  
Differential Regulation ◽  
Mrna Levels ◽  
Kinase C ◽  
External Signals ◽  
Nhe Isoforms ◽  
In Cells

Na+/H+ exchange (NHE) activity has been shown to be regulated by various external signals and protein kinases in many tissues and cell types. A family of six NHE isoforms has been identified. Three isoforms, NHE1, NHE2, and NHE3, have been shown to be expressed in the human intestine. The present studies were designed to study regulation of these human NHE isoforms by the α-isoform of protein kinase C (PKC) in the Caco-2 cell line. The mRNA levels of the NHE isoforms in Caco-2 cells were initially measured by a semiquantitative RT-PCR technique in response to PKC downregulation by long-term exposure to 1 μM 12- O-tetradecanoylphorbol-13-acetate (TPA) for 24 h. PKC downregulation resulted in an ∼60% increase in the mRNA level for NHE3, but not for NHE1 or NHE2. Utilizing dichlorobenzimidazole riboside, an agent to block the synthesis of new mRNA, we demonstrated that the increase in the NHE3 mRNA in response to downregulation of PKC was predominantly due to an increase in the rate of transcription, rather than a decrease in the NHE3 mRNA stability. Consistent with the mRNA results, our data showed that amiloride-sensitive22Na+ uptake was increased after incubation of Caco-2 cells with 1 μM TPA for 24 h. To elucidate the role of PKC-α, an isoform downregulated by TPA, the relative abundance of NHE isoform mRNA levels and the apical NHE activity were assessed in Caco-2 cells over- and underexpressing PKC-α. Our results demonstrated that NHE3, but not NHE1 or NHE2, mRNA was downregulated by PKC-α and that apical NHE activity was higher in cells underexpressing PKC-α and lower in cells overexpressing PKC-α than in control cells. In conclusion, these data demonstrate a differential regulation of NHE3, but not NHE2 or NHE1, expression by PKC in Caco-2 cells, and this regulation appears to be predominantly due to PKC-α.

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