Role of serotonin type 2 receptors in regulation of aldosterone production

1985 ◽  
Vol 249 (2) ◽  
pp. E234-E238 ◽  
Author(s):  
H. Matsuoka ◽  
M. Ishii ◽  
A. Goto ◽  
T. Sugimoto
Keyword(s):  
Serotonin Antagonists ◽  
Camp Production ◽  
Inhibitory Effects ◽  
Aldosterone Production ◽  
Dose Dependent Fashion ◽  
Dose Dependent

It is well recognized that serotonin stimulates aldosterone production by the adrenal glands. To investigate the possible roles of serotonin type 1 and 2 receptors in the regulation of aldosterone production, we examined the effects of cyproheptadine (a serotonin antagonist that inhibits both type 1 and 2 receptors) and ketanserin (a serotonin type 2 selective antagonist) on aldosterone and cAMP production in collagenase dispersed rat adrenal capsular cells. Serotonin, ranging in concentration from 10(-9) to 10(-3) M, significantly increased aldosterone production in a dose-dependent fashion after 2 h of incubation at 37 degrees C. Cyproheptadine and ketanserin showed comparable inhibitory effects on basal aldosterone production. These serotonin antagonists preferentially inhibited serotonin-induced aldosterone production. Serotonin significantly increased cAMP production at a dose of 10(-6) M. Both cyproheptadine and ketanserin significantly decreased basal cAMP production at doses of 10(-5) M. These serotonin antagonists preferentially inhibited serotonin-stimulated cAMP production. These results suggest that adrenal serotonin type 2 receptors may be coupled with adenylate cyclase activity and that these receptors are involved in the regulation of aldosterone production. Whether serotonin plays an important role in the regulation of aldosterone secretion in vivo remains to be elucidated.

Mg2+ activates the ryanodine receptor type 2 (RyR2) at intermediate Ca2+ concentrations

2007 ◽  
Vol 292 (1) ◽  
pp. C535-C544 ◽  
Author(s):  
Akihito Chugun ◽  
Osamu Sato ◽  
Hiroshi Takeshima ◽  
Yasuo Ogawa
Keyword(s):  
Cardiac Muscle ◽  
Ryanodine Receptor ◽  
Adenine Nucleotide ◽  
Receptor Type ◽  
Inhibitory Effects ◽  
Cardiac Muscles ◽  
Partial Suppression

To clarify whether activity of the ryanodine receptor type 2 (RyR2) is reduced in the sarcoplasmic reticulum (SR) of cardiac muscle, as is the case with the ryanodine receptor type 1 (RyR1), Ca2+-dependent [3H]ryanodine binding, a biochemical measure of Ca2+-induced Ca2+ release (CICR), was determined using SR vesicle fractions isolated from rabbit and rat cardiac muscles. In the absence of an adenine nucleotide or caffeine, the rat SR showed a complicated Ca2+ dependence, instead of the well-documented biphasic dependence of the rabbit SR. In the rat SR, [3H]ryanodine binding initially increased as [Ca2+] increased, with a plateau in the range of 10–100 μM Ca2+, and thereafter further increased to an apparent peak around 1 mM Ca2+, followed by a decrease. In the presence of these modulators, this complicated dependence prevailed, irrespective of the source. Addition of 0.3–1 mM Mg2+ unexpectedly increased the binding two- to threefold and enhanced the affinity for [3H]ryanodine at 10–100 μM Ca2+, resulting in the well-known biphasic dependence. In other words, the partial suppression of RyR2 is relieved by Mg2+. Ca2+ could be a substitute for Mg2+. Mg2+ also amplifies the responses of RyR2 to inhibitory and stimulatory modulators. This stimulating effect of Mg2+ on RyR2 is entirely new, and is referred to as the third effect, in addition to the well-known dual inhibitory effects. This effect is critical to describe the role of RyR2 in excitation-contraction coupling of cardiac muscle, in view of the intracellular Mg2+ concentration.

scholarly journals Functional Role of miR-155 in the Pathogenesis of Diabetes Mellitus and Its Complications

2021 ◽  
Vol 7 (3) ◽  
pp. 39
Author(s):  
Stanislovas S. Jankauskas ◽  
Jessica Gambardella ◽  
Celestino Sardu ◽  
Angela Lombardi ◽  
Gaetano Santulli
Keyword(s):  
Diabetes Mellitus ◽  
Metabolic Stress ◽  
Serum Levels ◽  
In Vitro Models ◽  
Preclinical Studies

Substantial evidence indicates that microRNA-155 (miR-155) plays a crucial role in the pathogenesis of diabetes mellitus (DM) and its complications. A number of clinical studies reported low serum levels of miR-155 in patients with type 2 diabetes (T2D). Preclinical studies revealed that miR-155 partakes in the phenotypic switch of cells within the islets of Langerhans under metabolic stress. Moreover, miR-155 was shown to regulate insulin sensitivity in liver, adipose tissue, and skeletal muscle. Dysregulation of miR-155 expression was also shown to predict the development of nephropathy, neuropathy, and retinopathy in DM. Here, we systematically describe the reports investigating the role of miR-155 in DM and its complications. We also discuss the recent results from in vivo and in vitro models of type 1 diabetes (T1D) and T2D, discussing the differences between clinical and preclinical studies and shedding light on the molecular pathways mediated by miR-155 in different tissues affected by DM.

scholarly journals Systemic Overexpression of IL-10 Induces CD4+CD25+ Cell Populations In Vivo and Ameliorates Type 1 Diabetes in Nonobese Diabetic Mice in a Dose-Dependent Fashion

2003 ◽  
Vol 171 (5) ◽  
pp. 2270-2278 ◽  
Author(s):  
Kevin S. Goudy ◽  
Brant R. Burkhardt ◽  
Clive Wasserfall ◽  
Sihong Song ◽  
Martha L. Campbell-Thompson ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Cell Populations ◽  
Diabetic Mice ◽  
Nonobese Diabetic ◽  
Dose Dependent Fashion ◽  
Nonobese Diabetic Mice ◽  
Dose Dependent

scholarly journals The role of microparticles in pathomechanisms of diabetic retinopathy – analysis of intercellular communication mechanisms in endothelial aging. Case control study in patients with metabolic syndrome, diabetes type 1 and type 2

2014 ◽  
Vol 83 (4) ◽  
pp. 322-327
Author(s):  
Ewa Stępień ◽  
Iwona Szuścik ◽  
Aleksandra Tokarz ◽  
Francisco J. Enguita ◽  
Bogdan Solnica ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Diabetic Retinopathy ◽  
Diabetic Patients ◽  
Imaging Method ◽  
Membrane Glycoproteins

The project is proposed to explain the role of specific circulating microparticles (MPs) as conveyors in trafficking bio-active molecules in type 1 (T1DM) and type 2 (T2DM) diabetic patients with risk of diabetic retinopathy (DR) and in patients with metabolic syndrome (MS). The possible role of miRNAs as modulators of these processes (in switching on/off mechanism on the molecular level) is proposed. An increased number of MPs with respect to glucose concentrations and levels of proangiogenic factors in vivo (patients’ plasma) is expected. The relationship between age of patents and MP content (cell membrane glycoproteins, phosphatidylserine or miRNA profile) is possible. MPs will be obtained from T1DM (n = 30) T2DM (n = 30), MS (n = 30) and controls (n = 30). Retinopathy in diabetic patients will be assessed by imaging method. Biological profile of MPs will be assessed in vitro by means of flow cytometry, molecular biology methods and cell proliferation assays.

scholarly journals Autoinduction of activin genes in early Xenopus embryos

1994 ◽  
Vol 298 (2) ◽  
pp. 275-280 ◽  
Author(s):  
A Suzuki ◽  
T Nagai ◽  
S I Nishimatsu ◽  
H Sugino ◽  
Y Eto ◽  
...  
Keyword(s):  
Gene Expression ◽  
Mrna Levels ◽  
Xenopus Embryos ◽  
Treatment Conditions ◽  
Dose Dependent Fashion ◽  
Polymerase Chain ◽  
Stage 1 ◽  
Dose Dependent

Activin exhibits a potent mesoderm inducing activity towards the ectodermal tissue (animal cap) of Xenopus laevis blastulae. Thus in order to investigate the role of activin in morphogenesis of early Xenopus embryos, activation of genes for activin beta A and beta B was examined by the reverse transcription polymerase chain reaction. In vivo, activin beta B mRNA appears to be present in embryonic stage 1 whereas beta A mRNA is undetectable prior to gastrulation. beta B and beta A mRNAs were noted to accumulate after stages 9 and 15 respectively. Activin gene expression in Xenopus animal caps was examined after treatment with various concentrations of activin A. Under these treatment conditions, both activin beta A and beta B mRNAs accumulated in a dose-dependent fashion after 24 h. The same effect was noted for treatment with similar concentrations of activin B. Accumulation of mRNAs was inhibited by the addition of cycloheximide to the culture medium, consistent with the proposition that activin gene expression requires certain protein factors. In total, therefore, these data suggest that an autoinduction mechanism is involved in the regulation of activin mRNA levels in normal Xenopus embryos and that this mechanism may play a pivotal role during early embryonic development.

Soluble Thrombomodulin Purified from Human Urine Exhibits a Potent Anticoagulant Effect In Vitro and In Vivo

1995 ◽  
Vol 73 (05) ◽  
pp. 805-811 ◽  
Author(s):  
Yasuo Takahashi ◽  
Yoshitaka Hosaka ◽  
Hiromi Niina ◽  
Katsuaki Nagasawa ◽  
Masaaki Naotsuka ◽  
...  
Keyword(s):  
Human Urine ◽  
Specific Activity ◽  
Anticoagulant Activity ◽  
Rabbit Lung ◽  
Soluble Thrombomodulin ◽  
Molecular Weights ◽  
Dose Dependent Fashion ◽  
Dose Dependent

SummaryWe examined the anticoagulant activity of two major molecules of soluble thrombomodulin purified from human urine. The apparent molecular weights of these urinary thrombomodulins (UTMs) were 72,000 and 79,000, respectively. Both UTMs showed more potent cofactor activity for protein C activation [specific activity >5,000 thrombomodulin units (TMU)/mg] than human placental thrombomodulin (2,180 TMU/mg) and rabbit lung thrombomodulin (1,980 TMU/mg). The UTMs prolonged thrombin-induced fibrinogen clotting time (>1 TMU/ml), APTT (>5 TMU/ml), TT (>5 TMU/ml) and PT (>40 TMU/ml) in a dose-dependent fashion. These effects appeared in the concentration range of soluble thrombomodulins present in human plasma and urine. In the rat DIC model induced by thromboplastin, administration of UTMs by infusion (300-3,000 TMU/kg) restored the hematological abnormalities derived from DIC in a dose-dependent fashion. These results demonstrate that UTMs exhibit potent anticoagulant and antithrombotic activities, and could play a physiologically important role in microcirculation.

scholarly journals Role of Oral Antioxidant Supplementation in the Current Management of Diabetic Retinopathy

2021 ◽  
Vol 22 (8) ◽  
pp. 4020
Author(s):  
Enrique Antonio Alfonso-Muñoz ◽  
Raquel Burggraaf-Sánchez de las Matas ◽  
Jorge Mataix Boronat ◽  
Julio César Molina Martín ◽  
Carmen Desco
Keyword(s):  
Diabetic Retinopathy ◽  
Diabetic Macular Oedema ◽  
Complementary Therapy ◽  
Antioxidant Supplementation ◽  
Current Management ◽  
Adult Type ◽  
Aged People

Oxidative stress has been postulated as an underlying pathophysiologic mechanism of diabetic retinopathy (DR), the main cause of avoidable blindness in working-aged people. This review addressed the current daily clinical practice of DR and the role of antioxidants in this practice. A systematic review of the studies on antioxidant supplementation in DR patients was presented. Fifteen studies accomplished the inclusion criteria. The analysis of these studies concluded that antioxidant supplementation has a IIB level of recommendation in adult Type 1 and Type 2 diabetes mellitus subjects without retinopathy or mild-to-moderate nonproliferative DR without diabetic macular oedema as a complementary therapy together with standard medical care.

scholarly journals EXPRESS: Pulmonary Hypertension Associated With Neurofibromatosis Type 2

2021 ◽  
pp. 204589402110295
Author(s):  
Hirohisa Taniguchi ◽  
Tomoya Takashima ◽  
Ly Tu ◽  
Raphaël Thuillet ◽  
Asuka Furukawa ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Neurofibromatosis Type ◽  
Pulmonary Vascular Remodeling ◽  
Life Threatening ◽  
History Of ◽  
Pulmonary Arterial ◽  
First Time

Although precapillary pulmonary hypertension (PH) is a rare but severe complication of patients with neurofibromatosis type 1 (NF1), its association with NF2 remains unknown. Herein, we report a case of a 44-year-old woman who was initially diagnosed with idiopathic pulmonary arterial hypertension (IPAH) and treated with PAH-specific combination therapy. However, a careful assessment for a relevant family history of the disease and genetic testing reveal that this patient had a mutation in the NF2 gene. Using immunofluorescence and Western blotting, we demonstrated a decrease in endothelial NF2 protein in lungs from IPAH patients compared to control lungs, suggesting a potential role of NF2 in PAH development. To our knowledge, this is the first time that precapillary PH has been described in a patient with NF2. The altered endothelial NF2 expression pattern in PAH lungs should stimulate work to better understand how NF2 is contributing to the pulmonary vascular remodeling associated to these severe life-threatening conditions.

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