The α2-adrenoceptor agonist dexmedetomidine increases the apparent potency of the volatile anesthetic isoflurane in rats in vivo and in hippocampal slice in vitro

Chronic stress exerts vagally dependent effects to disrupt gastric motility; previous studies have shown that, among other nuclei, A2 neurons are involved in mediating these effects. Several studies have also shown robust in vitro and in vivo effects of α2-adrenoceptor agonists on vagal motoneurons. We have demonstrated previously that brainstem vagal neurocircuits undergo remodeling following acute stress; however, the effects following brief periods of chronic stress have not been investigated. Our aim, therefore, was to test the hypothesis that different types of chronic stress influence gastric tone and motility by inducing plasticity in the response of vagal neurocircuits to α2-adrenoreceptor agonists. In rats that underwent 5 days of either homotypic or heterotypic stress loading, we applied the α2-adrenoceptor agonist, UK14304, either by in vitro brainstem perfusion to examine its ability to modulate GABAergic synaptic inputs to vagal motoneurons or in vivo brainstem microinjection to observe actions to modulate antral tone and motility. In neurons from naïve rats, GABAergic currents were unresponsive to exogenous application of UK14304. In contrast, GABAergic currents were inhibited by UK14304 in all neurons from homotypic and, in a subpopulation of neurons, heterotypic stressed rats. In control rats, UK14304 microinjection inhibited gastric tone and motility via withdrawal of vagal cholinergic tone; in heterotypic stressed rats, the larger inhibition of antrum tone was due to a concomitant activation of peripheral nonadrenergic, noncholinergic pathways. These data suggest that stress induces plasticity in brainstem vagal neurocircuits, leading to an upregulation of α2-mediated responses. NEW & NOTEWORTHY Catecholaminergic neurons of the A2 area play a relevant role in stress-related dysfunction of the gastric antrum. Brief periods of chronic stress load induce plastic changes in the actions of adrenoceptors on vagal brainstem neurocircuits.

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Desensitization of platelet α2-adrenoceptors after short term infusions of adrenoceptor agonist in man

Clinical Science ◽

10.1042/cs0700147 ◽

1986 ◽

Vol 70 (2) ◽

pp. 147-153 ◽

Cited By ~ 18

Author(s):

C. R. Jones ◽

M. Giembcyz ◽

C. A. Hamilton ◽

I. W. Rodger ◽

K. Whyte ◽

...

Keyword(s):

Binding Sites ◽

Human Platelet ◽

Short Term ◽

Α2 Adrenoceptor ◽

Adrenoceptor Agonist ◽

Adrenoceptor Agonists ◽

Adrenaline Infusion ◽

And Function

1. The effect of intravenous infusion of catecholamines and related drugs on human platelet α2-adrenoceptor number and function was investgated. 2. Short (60–120 min) infusions of catecholamines with α2 agonist activity in vivo produced attenuation of the platelet responses to adrenaline in vitro. This desensitization was specific for the adrenaline induced aggregatory response. 3. The maximum number of [3H]yohimbine binding sites on platelets was not altered by adrenaline infusion. 4. The ability of adrenaline to reduce platelet cyclic AMP levels was significantly reduced after the infusions. 5. Acute infusions of α2-adrenoceptor agonists may alter the coupling of the platelet α2-adrenoceptor to adenylate cyclase.

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In vitro and in vivo profiling of fadolmidine, a novel potent α2-adrenoceptor agonist with local mode of action

European Journal of Pharmacology ◽

10.1016/j.ejphar.2008.10.003 ◽

2008 ◽

Vol 599 (1-3) ◽

pp. 65-71 ◽

Cited By ~ 14

Author(s):

Jyrki Lehtimäki ◽

Tiina Leino ◽

Ari Koivisto ◽

Timo Viitamaa ◽

Tarja Lehtimäki ◽

...

Keyword(s):

Mode Of Action ◽

Local Mode ◽

Α2 Adrenoceptor ◽

Adrenoceptor Agonist

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Significance of Platelet β-Adrenoceptors for Platelet Responses In Vivo and In Vitro

Thrombosis and Haemostasis ◽

10.1055/s-0038-1646345 ◽

1992 ◽

Vol 68 (06) ◽

pp. 687-693 ◽

Cited By ~ 24

Author(s):

P T Larsson ◽

N H Wallén ◽

A Martinsson ◽

N Egberg ◽

P Hjemdahl

Keyword(s):

Ex Vivo ◽

High Dose ◽

Platelet Aggregability ◽

Adrenoceptor Agonist ◽

Dose Infusion ◽

Von Willebrand ◽

Willebrand Factor ◽

Factor Antigen

SummaryThe significance of platelet β-adrenoceptors for platelet responses to adrenergic stimuli in vivo and in vitro was studied in healthy volunteers. Low dose infusion of the β-adrenoceptor agonist isoprenaline decreased platelet aggregability in vivo as measured by ex vivo filtragometry. Infusion of adrenaline, a mixed α- and β-adrenoceptor agonist, increased platelet aggregability in vivo markedly, as measured by ex vivo filtragometry and plasma β-thromboglobulin levels. Adrenaline levels were 3–4 nM in venous plasma during infusion. Both adrenaline and high dose isoprenaline elevated plasma von Willebrand factor antigen levels β-Blockade by propranolol did not alter our measures of platelet aggregability at rest or during adrenaline infusions, but inhibited adrenaline-induced increases in vWf:ag. In a model using filtragometry to assess platelet aggregability in whole blood in vitro, propranolol enhanced the proaggregatory actions of 5 nM, but not of 10 nM adrenaline. The present data suggest that β-adrenoceptor stimulation can inhibit platelet function in vivo but that effects of adrenaline at high physiological concentrations are dominated by an α-adrenoceptor mediated proaggregatory action.

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Molecular Aspects of Volatile Anesthetic-Induced Organ Protection and Its Potential in Kidney Transplantation

International Journal of Molecular Sciences ◽

10.3390/ijms22052727 ◽

2021 ◽

Vol 22 (5) ◽

pp. 2727

Author(s):

Gertrude J. Nieuwenhuijs-Moeke ◽

Dirk J. Bosch ◽

Henri G.D. Leuvenink

Keyword(s):

Kidney Transplantation ◽

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

Animal Experiments ◽

Volatile Anesthetic ◽

Organ Protection ◽

Graft Outcome ◽

Molecular Aspects

Ischemia reperfusion injury (IRI) is inevitable in kidney transplantation and negatively impacts graft and patient outcome. Reperfusion takes place in the recipient and most of the injury following ischemia and reperfusion occurs during this reperfusion phase; therefore, the intra-operative period seems an attractive window of opportunity to modulate IRI and improve short- and potentially long-term graft outcome. Commonly used volatile anesthetics such as sevoflurane and isoflurane have been shown to interfere with many of the pathophysiological processes involved in the injurious cascade of IRI. Therefore, volatile anesthetic (VA) agents might be the preferred anesthetics used during the transplantation procedure. This review highlights the molecular and cellular protective points of engagement of VA shown in in vitro studies and in vivo animal experiments, and the potential translation of these results to the clinical setting of kidney transplantation.

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Sevoflurane inhibits malignant progression of colorectal cancer via hsa_circ_0000231-mediated miR-622

Journal of Biological Research-Thessaloniki ◽

10.1186/s40709-021-00145-6 ◽

2021 ◽

Vol 28 (1) ◽

Author(s):

Jingpeng Wang ◽

Shuyuan Li ◽

Gaofeng Zhang ◽

Huihua Han

Keyword(s):

Colorectal Cancer ◽

Cell Proliferation ◽

Cell Apoptosis ◽

Volatile Anesthetic ◽

Tumor Formation ◽

Luciferase Reporter ◽

Migration And Invasion ◽

Circular Rnas

Abstract Background Sevoflurane (Sev), a commonly used volatile anesthetic, has been reported to inhibit the process of colorectal cancer (CRC). Circular RNAs (circRNAs) are revealed to participate in the pathogenesis of CRC. This study aims to reveal the mechanism of hsa_circ_0000231 in Sev-mediated CRC progression. Methods The expression of hsa_circ_0000231 and microRNA-622 (miR-622) was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Protein level was determined by western blot analysis. Cell proliferation was investigated by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), cell colony formation and DNA content quantitation assays. Cell apoptosis was detected by Annexin V-fluorescein isothiocyanate and propidium iodide double staining and caspase 3 activity assays. Cell migration and invasion were investigated by wound-healing and transwell invasion assays, respectively. The putative relationship between hsa_circ_0000231 and miR-622 was predicted by circular RNA Interactome online database, and identified by dual-luciferase reporter and RNA immunoprecipitation assays. The impacts of hsa_circ_0000231 on Sev-mediated tumor formation in vivo were presented by in vivo assay. Results Hsa_circ_0000231 expression was upregulated, while miR-622 was downregulated in CRC tissues and cells compared with control groups. Sev treatment decreased hsa_circ_0000231 expression, but increased miR-622 expression in CRC cells. Sev treatment suppressed cell proliferation, migration and invasion, and induced cell apoptosis. Hsa_circ_0000231 overexpression restored Sev-mediated CRC progression in vitro. Additionally, hsa_circ_0000231 acted as a sponge of miR-622, and miR-622 inhibitors reversed the impacts of hsa_circ_0000231 silencing on CRC process. Furthermore, Sev treatment inhibited tumor growth by regulating hsa_circ_0000231 in vivo. Conclusion Hsa_circ_0000231 attenuated Sev-aroused repression impacts on CRC development by sponging miR-622. This findings may provide an appropriate anesthetic protocol for CRC sufferers undergoing surgery.

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