Serotonin antagonists induce anxiolytic and anxiogenic-like behavior in zebrafish in a receptor-subtype dependent manner

2014 ◽  
Vol 126 ◽  
pp. 170-180 ◽  
Author(s):  
Magda Nowicki ◽  
Steven Tran ◽  
Arrujyan Muraleetharan ◽  
Stefan Markovic ◽  
Robert Gerlai
Keyword(s):  
Receptor Subtype ◽  
Dependent Manner ◽  
Serotonin Antagonists

scholarly journals Ghrelin Receptor (GHS-R1a) and Its Constitutive Activity in Somatotroph Adenomas: A New Co-targeting Therapy Using GHS-R1a Inverse Agonists and Somatostatin Analogs

2014 ◽  
Vol 99 (12) ◽  
pp. E2463-E2471 ◽  
Author(s):  
Yves Mear ◽  
Marie-Pierre Blanchard ◽  
Céline Defilles ◽  
Thierry Brue ◽  
Dominique Figarella-Branger ◽  
...  
Keyword(s):  
Somatostatin Receptor ◽  
Somatostatin Analogs ◽  
Inverse Agonist ◽  
Receptor Subtype ◽  
Dependent Manner ◽  
Constitutive Activity ◽  
Targeting Therapy ◽  
Ghrelin Receptor ◽  
Gh Secretion

Context: The ghrelin receptor GHS-R1a is highly expressed in human somatotroph adenomas and exhibits unusually high basal signaling activity. In humans, the suppression of this constitutive activity by mutation induces a short stature. Objective: Using a GHS-R1a inverse agonist, modified substance P (MSP), we explored the role of GHS-R1a constitutive activity in GH hypersecretion from somatotroph adenomas and as a putative therapeutic target. Design: The effects of MSP were assessed on GH secretion from 19 human somatotroph tumors in vitro. Moreover, these effects were compared with those of octreotide (somatostatin receptor subtype 2 [sst2] agonist) and with the combination of both drugs. Expression and localization of GHS-R1a and sst2 were studied. Results: For all tumors, MSP inhibited GH secretion in a dose-dependent manner from 13 to 64%. Moreover, MSP enhanced octreotide-induced GH inhibition. For five tumors, the effects of combined MSP plus octreotide treatment were significantly higher than the sum of effects of each drug alone. MSP increased the membrane localization of GHS-R1a and of microdomains colocalizing sst2-GHS-R1a, highlighting the cooperation between the two drugs. Conclusions: The GHS-R1a inverse agonist could open new therapeutic options for acromegalic patients, particularly patients partially sensitive to octreotide whose GH secretion is not completely controlled by the sst2 agonist.

Epinephrine Stimulates Cell Proliferation and Induces Chemoresistance in Myeloma Cells through the β-Adrenoreceptor in vitro

2017 ◽  
Vol 138 (2) ◽  
pp. 103-110 ◽  
Author(s):  
Yang Liu ◽  
Xiaochen Yu ◽  
Junling Zhuang
Keyword(s):  
Cell Proliferation ◽  
Cell Growth ◽  
Cell Line ◽  
Receptor Subtype ◽  
Dependent Manner ◽  
Myeloma Cells ◽  
U266 Cell ◽  
Β Receptor ◽  
U266 Cell Line

Objectives: To explore the effect of the β-adrenoreceptor signaling pathway on myeloma cells. Methods: The myeloma U266 cell line was treated with epinephrine and propranolol. Cell proliferation was analyzed by MTS assay. Apoptosis was detected by flow cytometry. The β-receptor subtype and the key enzyme of epinephrine were identified by reverse transcription polymerase chain reaction (RT-PCR). Results: Epinephrine (5-50 μM) promoted U266 cell growth in a dose-dependent manner and neutralized the inhibition effect of bortezomib (25 and 50 ng/mL) in vitro. Cell proliferation was inhibited by a β-receptor antagonist, propranolol, at a concentration of 50-200 μM. The proportions of early and late apoptotic cells were enhanced after treatment with propranolol. The expression of caspase 3/7, 8, and 9 was elevated in propranolol-treated myeloma cells. Both β1- and β2-adrenoceptor mRNAs were expressed in the U266 cell line. Key enzymes dopamine hydroxylase and tyrosinehydroxylase were identified in myeloma cells. Conclusions: Our results reveal that epinephrine stimulates myeloma cell growth in vitro while the β-blocker propranolol has an antiproliferative effect, indicating that stress hormones may trigger the progression of myeloma.

Characterization of angiotensin receptors mediating prostaglandin synthesis in C6 glioma cells

1991 ◽  
Vol 260 (5) ◽  
pp. R1000-R1006 ◽  
Author(s):  
N. Jaiswal ◽  
D. I. Diz ◽  
E. A. Tallant ◽  
M. C. Khosla ◽  
C. M. Ferrario
Keyword(s):  
Glioma Cells ◽  
C6 Glioma ◽  
C6 Glioma Cells ◽  
Angiotensin Receptors ◽  
Receptor Subtype ◽  
Receptor Subtypes ◽  
Dependent Manner ◽  
Ang Ii ◽  
Selective Antagonist ◽  
Pge2 Release

The heptapeptide angiotensin (ANG)-(1-7) mimics some but not all the central actions of ANG II, suggesting that receptor subtypes may exist. The effects of ANG-(1-7), ANG II, and ANG I on prostaglandin (PG) E2 and prostacyclin (PGI2) synthesis were investigated in neurally derived rat C6 glioma cells. All three ANG peptides stimulated PG release in a dose-dependent manner with the order of potency ANG-(1-7) greater than ANG I greater than ANG II. PGE2 release induced by ANG-(1-7) (10(-7) M) was partially blocked by [Sar1,Ile8]ANG II (10(-6) M), [Sar1,Thr8]ANG II (10(-6) M), or the subtype 1 selective antagonist Du Pont 753 (10(-5) M) but not by the subtype 2 selective antagonist CGP 42112A (10(-7)-10(-5) M). PGI2 release was inhibited only by [Sar1,Thr8]ANG II. ANG II-induced PGE2 release was blocked by [Sar1,Thr8]ANG II (10(-6) M), [Sar1,Ile8]ANG II (10(-6) M), or Du Pont 753 (10(-7) M) but not by CGP 42112A (10(-7)-10(-5) M). In contrast, ANG II-induced PGI2 release was blocked by Du Pont 753 (10(-7) M) as well as [Sar1,Ile8]ANG II (10(-6) M) but not by [Sar1,Thr8]ANG II or CGP 42112A. Thus ANG II-stimulated PGE2 and PGI2 syntheses in C6 glioma cells are mediated via receptor subtype 1. ANG-(1-7)-induced PGE2 synthesis is also mediated via subtype 1 receptors; however, PGI2 release was blocked by [Sar1,Thr8]ANG II only.(ABSTRACT TRUNCATED AT 250 WORDS)

Microinjection of exogenous somatostatin in the dorsal vagal complex inhibits pancreatic secretion via somatostatin receptor-2 in rats

2007 ◽  
Vol 292 (3) ◽  
pp. G746-G752 ◽  
Author(s):  
Zhuan Liao ◽  
Zhao-Shen Li ◽  
Yan Lu ◽  
Wei-Zhong Wang
Keyword(s):  
Pancreatic Secretion ◽  
Exocrine Pancreas ◽  
Feedback Inhibition ◽  
Somatostatin Receptor ◽  
Inhibitory Effect ◽  
Receptor Subtype ◽  
Dependent Manner ◽  
Dorsal Vagal Complex ◽  
Somatostatin Receptor Antagonist ◽  
Dose Dependent

Previous studies have suggested that somatostatin inhibits pancreatic secretion at a central vagal site, and the dorsal vagal complex (DVC) is involved in central feedback inhibition of the exocrine pancreas. The aim of this study was to investigate the effect of exogenous somatostatin in the DVC on pancreatic secretion and the somatostatin receptor subtype(s) responsible for the effect. The effects of somatostatin microinjected into the DVC on pancreatic secretion stimulated by cholecystokinin octapeptide (CCK-8) or 2-deoxy-d-glucose (2-DG) were examined in anesthetized rats. To investigate the somatostatin inhibitory action site, a somatostatin receptor antagonist [SRA; cyclo(7-aminoheptanoyl-Phe-d-Trp-Lys-Thr)] was microinjected into the DVC before intravenous infusion of somatostatin and CCK-8/2-DG. The effects of injection of a somatostatin receptor-2 agonist (seglitide) and combined injection of somatostatin and a somatostatin receptor-2 antagonist (CYN 154806) in the DVC on the pancreatic secretion were also investigated. Somatostatin injected into the DVC significantly inhibited pancreatic secretion evoked by CCK-8 or 2-DG in a dose-dependent manner. SRA injected into the DVC completely reversed the inhibitory effect of intravenous administration of somatostatin. Seglitide injected into the DVC also inhibited CCK-8/2-DG-induced pancreatic protein secretion. However, combined injection of somatostatin and CYN 154806 did not affect the CCK-8/2-DG-induced pancreatic secretion. Somatostatin in the DVC inhibits pancreatic secretion via somatostatin receptor-2, and the DVC is the action site of somatostatin for its inhibitory effect.

scholarly journals Activation of TRPA1 by luminal stimuli induces EP4-mediated anion secretion in human and rat colon

2012 ◽  
Vol 302 (7) ◽  
pp. G690-G701 ◽  
Author(s):  
Izumi Kaji ◽  
Yukiko Yasuoka ◽  
Shin-ichiro Karaki ◽  
Atsukazu Kuwahara
Keyword(s):  
Host Defense ◽  
Transient Receptor Potential ◽  
Defense Mechanism ◽  
Ussing Chamber ◽  
Pcr Analysis ◽  
Rat Colon ◽  
Receptor Subtype ◽  
Neural Pathways ◽  
Dependent Manner ◽  
Anion Secretion

In gastrointestinal (GI) physiology, anion and fluid secretion is an important function for host defense and is induced by changes in the luminal environment. The transient receptor potential A1 (TRPA1) channel is considered to be a chemosensor in several sensory tissues. Although the function of TRPA1 has been studied in GI motility, its contribution to the transepithelial ion transport system has rarely been discussed. In the present study, we investigated the secretory effect of the potential TRPA1 agonist allyl isothiocyanate (AITC) in rat and human colon using an Ussing chamber. The mucosal application of AITC (10−6-10−3 M) induced Cl− and HCO3− secretion in a concentration-dependent manner, whereas the serosal application induced a significantly weaker effect. AITC-evoked anion secretion was attenuated by tissue pretreatment with piroxicam and prostaglandin (PG) E2; however, this secretion was not affected by TTX, atropine, or extracellular Ca2+ depletion. These experiments indicate that TRPA1 activation induces anion secretion through PG synthesis, independent of neural pathways in the colon. Further analysis also indicates that AITC-evoked anion secretion is mediated mainly by the EP4 receptor subtype. The magnitude of the secretory response exhibited segmental heterogeneity in rat colon. Real-time PCR analysis showed the segmental difference was corresponding to the differential expression of EP4 receptor and cyclooxygenase-1 and -2. In addition, RT-PCR, in situ hybridization, and immunohistochemical studies showed TRPA1 expression in the colonic epithelia. Therefore, we conclude that the activation of TRPA1 in colonic epithelial cells is likely involved in the host defense mechanism through rapid anion secretion.

scholarly journals Calcitonin Induces IL-6 Production via Both PKA and PKC Pathways in the Pituitary Folliculo-Stellate Cell Line

Endocrinology ◽  
2001 ◽  
Vol 142 (8) ◽  
pp. 3563-3569 ◽  
Author(s):  
Yoshimitsu Kiriyama ◽  
Hiroyuki Tsuchiya ◽  
Takeshi Murakami ◽  
Kumi Satoh ◽  
Yukiko Tokumitsu
Keyword(s):  
Cell Line ◽  
Stellate Cell ◽  
Fold Increase ◽  
Receptor Subtype ◽  
Dependent Manner ◽  
Calcitonin Receptor ◽  
Rt Pcr ◽  
Concentration Dependent Manner ◽  
Mouse Pituitary ◽  
Inhibitor Treatment

Abstract It has been demonstrated that calcitonin-binding sites are present in a variety of tissue types, including in the pituitary gland. Interleukin-6 (IL-6) is also produced in the pituitary and it regulates the secretion of various hormones. In this study, we examined the expression of the calcitonin receptor and the mechanism of IL-6 production induced by calcitonin in the pituitary folliculo-stellate cell line (TtT/GF). The mRNA of calcitonin receptor subtype C1a, but not that of C1b, was detected by RT-PCR in TtT/GF cells and in the normal mouse pituitary. Calcitonin increased cAMP accumulation and IL-6 production in a concentration-dependent manner in TtT/GF cells. As calcitonin activates the PKA and PKC pathways, we investigated the contributions of PKA and PKC to IL-6 production. IL-6 production was only slightly increased by either 8-bromo-cAMP (1 mm) or phorbol 12-myristate 13-acetate (100 nm) alone. However, IL-6 was synergistically induced in the presence of both 8-bromo-cAMP (1 mm) and phorbol 12myristate 13-acetate (100 nm). Furthermore, calcitonin-induced IL-6 production was completely suppressed by H-89 (PKA inhibitor) or GF109203X (PKC inhibitor), indicating that the activation of both PKA and PKC is necessary for calcitonin-induced IL-6 production. On the other hand, pertussis toxin (Gi/Go signaling inhibitor) treatment achieved an approximately 9-fold increase in calcitonin-induced IL-6 production. These results show that calcitonin-stimulated IL-6 production is mediated via both PKA- and PKC-signaling pathways, whereas calcitonin also suppresses IL-6 production by activating Gi/Go proteins in folliculo-stellate cells.

scholarly journals Angiotensin II-Induced Mitogen-Activated Protein Kinase Phosphatase-1 Expression in Bovine Adrenal Glomerulosa Cells: Implications in Mineralocorticoid Biosynthesis

Endocrinology ◽  
2007 ◽  
Vol 148 (11) ◽  
pp. 5573-5581 ◽  
Author(s):  
Andrés J. Casal ◽  
Stéphane Ryser ◽  
Alessandro M. Capponi ◽  
Carine F. Wang-Buholzer
Keyword(s):  
Angiotensin Ii ◽  
Mapk Pathway ◽  
Fold Increase ◽  
Zona Glomerulosa ◽  
Mitogen Activated Protein Kinase ◽  
Receptor Subtype ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Aldosterone Production ◽  
Glomerulosa Cells

Angiotensin II (AngII) stimulates aldosterone biosynthesis in the zona glomerulosa of the adrenal cortex. AngII also triggers the MAPK pathways (ERK1/2 and p38). Because ERK1/2 phosphorylation is a transient process, phosphatases could play a crucial role in the acute steroidogenic response. Here we show that the dual specificity (threonine/tyrosine) MAPK phosphatase-1 (MKP-1) is present in bovine adrenal glomerulosa cells in primary culture and that AngII markedly increases its expression in a time- and concentration-dependent manner (IC50 = 1 nm), a maximum of 548 ± 10% of controls being reached with 10 nm AngII after 3 h (n = 3, P < 0.01). This effect is completely abolished by losartan, a blocker of the AT1 receptor subtype. Moreover, this AngII-induced MKP-1 expression is reduced to 250 ± 35% of controls (n = 3, P < 0.01) in the presence of U0126, an inhibitor of ERK1/2 phosphorylation, suggesting an involvement of the ERK1/2 MAPK pathway in MKP-1 induction. Indeed, shortly after AngII-induced phosphorylation of ERK1/2 (220% of controls at 30 min), MKP-1 protein expression starts to increase. This increase is associated with a reduction in ERK1/2 phosphorylation, which returns to control values after 3 h of AngII challenge. Enhanced MKP-1 expression is essentially due to a stabilization of MKP-1 mRNA. AngII treatment leads to a 53-fold increase in phosphorylated MKP-1 levels and a doubling of MKP-1 phosphatase activity. Overexpression of MKP-1 results in decreased phosphorylation of ERK1/2 and aldosterone production in response to AngII stimulation. These results strongly suggest that MKP-1 is the specific phosphatase induced by AngII and involved in the negative feedback mechanism ensuring adequate ERK1/2-mediated aldosterone production in response to the hormone.

scholarly journals Doxorubicin acts through tumor necrosis factor receptor subtype 1 to cause dysfunction of murine skeletal muscle

2009 ◽  
Vol 107 (6) ◽  
pp. 1935-1942 ◽  
Author(s):  
Laura A. A. Gilliam ◽  
Leonardo F. Ferreira ◽  
Joseph D. Bruton ◽  
Jennifer S. Moylan ◽  
Håkan Westerblad ◽  
...  
Keyword(s):  
Tumor Necrosis Factor ◽  
Muscle Weakness ◽  
Tumor Necrosis ◽  
Elevated Serum ◽  
Receptor Subtype ◽  
Dependent Manner ◽  
Limb Muscle ◽  
Main Hypothesis ◽  
Doxorubicin Administration ◽  
Necrosis Factor

Cancer patients receiving doxorubicin chemotherapy experience both muscle weakness and fatigue. One postulated mediator of the muscle dysfunction is an increase in tumor necrosis factor-α (TNF), a proinflammatory cytokine that mediates limb muscle contractile dysfunction through the TNF receptor subtype 1 (TNFR1). Our main hypothesis was that systemic doxorubicin administration would cause muscle weakness and fatigue. Systemic doxorubicin administration (20 mg/kg) depressed maximal force of the extensor digitorum longus (EDL; P < 0.01), accelerated EDL fatigue ( P < 0.01), and elevated serum TNF levels ( P < 0.05) 72 h postinjection. Genetic TNFR1 deficiency prevented the fall in specific force caused by systemic doxorubicin, without protecting against fatigue ( P < 0.01). These results demonstrate that clinical doxorubicin concentrations disrupt limb muscle function in a TNFR1-dependent manner.

scholarly journals Agonist-induced desensitization and phosphorylation of m1-muscarinic receptors

1999 ◽  
Vol 338 (1) ◽  
pp. 175-183 ◽  
Author(s):  
Mark G. WAUGH ◽  
R. A. John CHALLISS ◽  
Gabriel BERSTEIN ◽  
Stefan R. NAHORSKI ◽  
Andrew B. TOBIN
Keyword(s):  
Muscarinic Receptor ◽  
Muscarinic Receptors ◽  
Chinese Hamster ◽  
Receptor Internalization ◽  
Receptor Subtype ◽  
Muscarinic Agonist ◽  
Dependent Manner ◽  
Receptor Desensitization ◽  
M1 Muscarinic ◽  
M1 Muscarinic Receptors

Pre-stimulation of Chinese hamster ovary (CHO) cells expressing the human m1-muscarinic receptor (CHO-m1 cells) with a maximally effective concentration of the muscarinic agonist methacholine resulted in desensitization of Ins(1,4,5)P3 accumulation, apparent as a ∼ 4-fold shift in the agonist dose–response curve. Agonist-induced desensitization was rapid (detectable by 10 s) and concentration dependent (EC50 = 8.2±2.2 µM) and resulted in a complete loss of receptor reserve for the agonist-stimulated Ins(1,4,5)P3 response. An investigation of the possible mechanisms involved in m1-muscarinic receptor desensitization indicated that agonist-induced receptor internalization, PtdIns-(4,5)P2 depletion or an increased rate of Ins(1,4,5)P3 metabolism were not involved. m1-Muscarinic receptors did, however, undergo rapid agonist-induced phosphorylation with a time course that was consistent with an involvement in receptor desensitization. Characterization studies indicated that the receptor-specific kinase involved was distinct from protein kinase C and other second-messenger-dependent protein kinases. Since previous studies have suggested that the m3-muscarinic receptor subtype undergoes agonist-dependent phosphorylation via casein kinase 1α (CK1α) [Tobin, Totty, Sterlin and Nahorski (1997) J. Biol. Chem. 272, 20844–20849], we examined the ability of m1-muscarinic receptors to be phosphorylated by this kinase. In reconstitution experiments, CK1α was able to phosphorylate purified, soluble m1-muscarinic receptors in an agonist-dependent manner.

Rosiglitazone protects rat liver against acute liver injury associated with the NF-κB signaling pathway

2016 ◽  
Vol 94 (1) ◽  
pp. 28-34 ◽  
Author(s):  
Wei Chen ◽  
Yuan-Jie Lin ◽  
Xu-Ya Zhou ◽  
Hao Chen ◽  
Yong Jin
Keyword(s):  
Liver Injury ◽  
Signaling Pathway ◽  
Rat Liver ◽  
Receptor Subtype ◽  
Histopathological Analysis ◽  
Peroxisome Proliferator ◽  
Dependent Manner ◽  
Protective Effects ◽  
Sprague Dawley ◽  
Serum Aminotransferase

Rosiglitazone, which is mainly used in the treatment of diabetes mellitus, is also involved in the regulation of inflammation. The peroxisome proliferator-activated receptor (PPAR)-γ receptor subtype appears to play a pivotal role in the regulation of inflammation. However, the exact mechanism for the protective effects of rosiglitazone against inflammation such as liver injury remains unclear. The aim of this study was to investigate the effects of rosiglitazone on inflammation in the liver of rats treated with D-GaIN/LPS. Male Sprague–Dawley rats were injected with D-GaIN/LPS with or without pre-administration of rosiglitazone (3, 10, or 30 mg/kg, intraperitoneal injection). Our data showed that rosiglitazone significantly inhibited D-GaIN/LPS-induced hepatotoxicity in a dose-dependent manner, as indicated by both diagnostic indicators of liver damage (serum aminotransferase activities) and histopathological analysis. Western blot analysis showed that rosiglitazone significantly decreased protein expression levels of COX-2 and production of pro-inflammatory markers, including TNF-α and IL-6, in D-GaIN/LPS-treated rat liver. The results indicated that the inhibition of D-GaIN/LPS-induced inflammation by rosiglitazone can be attributed, at least partially, to its capacity to regulate the the immunoregulatory transcription factor nuclear factor kappa B (NF-κB) signaling pathway.

Sign in / Sign up

Export Citation Format

Share Document