JavaScript NENÍ povolen !

* Zobrazit nápovědu

10 záznamů v Medvik Filtry

Článek

Blockade of alpha2-adrenergic receptors in the caudal raphe region enhances the renal sympathetic nerve activity response to acute intermittent hypercapnia in rats

Madirazza, Katarina
Autor Madirazza, Katarina Department of Neuroscience, University of Split School of Medicine, Split, Croatia
Pecotic, Renata
Autor Pecotic, Renata Department of Neuroscience, University of Split School of Medicine, Split, Croatia
Pavlinac Dodig, Ivana
Autor Pavlinac Dodig, Ivana Department of Neuroscience, University of Split School of Medicine, Split, Croatia
Valic, Maja
Autor Valic, Maja Department of Neuroscience, University of Split School of Medicine, Split, Croatia
Dogas, Zoran
Autor Dogas, Zoran Department of Neuroscience, University of Split School of Medicine, Split, Croatia

Physiological research. 2022 ; 71 (1) : 159-169. [pub] 20220119

Physiol. Res. (Print)
ISSN 1802-9973
Medvik
Zdroj

The study investigated the role of alpha2-adrenergic receptors of the caudal raphe region in the sympathetic and cardiovascular responses to the acute intermittent hypercapnia (AIHc). Urethane-anesthetized, vagotomized, mechanically ventilated Sprague-Dawley rats (n=38) were exposed to the AIHc protocol (5×3 min, 15 % CO2+50 % O2) in hyperoxic background (50 % O2). alpha2-adrenergic receptor antagonist-yohimbine was applied intravenously (1 mg/kg, n=9) or microinjected into the caudal raphe region (2 mM, n=12) prior to exposure to AIHc. Control groups of animals received saline intravenously (n=7) or into the caudal raphe region (n=10) prior to exposure to AIHc. Renal sympathetic nerve activity (RSNA), mean arterial pressure (MAP) and heart rate (HR) were monitored before exposure to the AIHc protocol (T0), during five hypercapnic episodes (THc1-5) and at 15 min following the end of the last hypercapnic episode (T15). Following intravenous administration of yohimbine, RSNA was significantly greater during THc1-5 and at T15 than in the control group (P<0.05). When yohimbine was microinjected into the caudal raphe region, AIHc elicited greater increases in RSNA during THc1-5 when compared to the controls (THc1: 138.0+/-4.0 % vs. 123.7+/-4.8 %, P=0.032; THc2: 137.1+/-5.0 % vs. 124.1+/-4.5 %, P=0.071; THc3: 143.1+/-6.4 % vs. 122.0±4.8 %, P=0.020; THc4: 146.1+/-6.2 % vs. 120.7+/-5.7 %, P=0.007 and THc5: 143.2+/-7.7 % vs. 119.2+/-7.2 %, P=0.038). During THc1-5, significant decreases in HR from T0 were observed in all groups, while changes in MAP were observed in the group that received yohimbine intravenously. These findings suggest that blockade of the alpha2-adrenegic receptors in the caudal raphe region might have an important role in sympathetic responses to AIHc.

Článek

Modulation of Cough Reflex by Gaba-Ergic Inhibition in Medullary Raphé of the Cat

Physiological research. 2020 ; 69 (Suppl 1) : S151-S161. [pub] 20200327

Physiol. Res. (Print)
ISSN 1802-9973
Medvik
Zdroj

We studied the effects of GABA receptor agonists microinjections in medullary raphé on the mechanically induced tracheobronchial cough response in anesthetized, unparalyzed, spontaneously breathing cats. The results suggest that GABA-ergic inhibition significantly contributes to the regulation of cough reflex by action of both GABA(A) and GABA(B) receptors. The data are consistent with inhomogeneous occurrence of GABA-ergic neurons in medullary raphé and their different involvement in the cough reflex control. Cells within rostral nucleus raphéobscurus with dominant role of GABA(A) receptors and neurons of rostral nucleus raphépallidus and caudal nucleus raphémagnus with dominant role of GABA(B) receptors participate in regulation of cough expiratory efforts. These cough control elements are distinct from cough gating mechanism. GABA-ergic inhibition in the raphé caudal to obex had insignificant effect on cough. Contradictory findings for GABA, muscimol and baclofen administration in medullary raphé suggest involvement of coordinated activity of GABA on multiple receptors affecting raphé neurons and/or the local neuronal circuits in the raphé modulating cough motor drive.

MeSH
agonisté receptorů GABA-A farmakologie terapeutické užití MeSH
agonisté receptorů GABA-B farmakologie terapeutické užití MeSH
baklofen farmakologie terapeutické užití MeSH
kašel farmakoterapie patofyziologie MeSH
kočky MeSH
medulla oblongata účinky léků fyziologie MeSH
muscimol farmakologie terapeutické užití MeSH
nuclei raphe účinky léků fyziologie MeSH
receptory GABA-A fyziologie MeSH
receptory GABA-B fyziologie MeSH
reflex účinky léků fyziologie MeSH
zvířata MeSH
Check Tag
kočky MeSH
zvířata MeSH
Publikační typ
časopisecké články MeSH

Článek

Relationship between rapheal echogenicity and personality as possible markers of a disposition to develop depressive and anxiety disorders

Psychiatry research. Neuroimaging. 2017 ; 263 (-) : 70-75. [pub] 20170327

Psychiatry Res Neuroimaging
ISSN 1872-7506
Medvik
Zdroj

Early diagnosis of anxiety and depression may be facilitated by the use of neurobiological markers. In depression and panic disorder, transcranial sonography (TCS) has revealed decreased echogenicity of the brainstem raphe (BR). The aim of the present study was to detect whether decreased echogenicity of the BR correlates with personality features described in the five-dimension model, especially neuroticism. We examined 100 healthy volunteers using quantitative and qualitative TCS, the five-dimension revised NEO Personality Inventory, Beck´s scales of anxiety and depression, and the Social Re-adjustment Rating Scale (SRRS). Visual BR anechogenicity was found in 11 subjects, BR hypoechogenicity in 29 subjects, and normal BR echogenicity in 60 subjects. The visual assessment correlated with the digital assessment. Comparing the groups with visual BR anechogenicity and BR normoechogenicity, only increased SRRS score and increased agreeableness z-score were significant. Our hypothesis that BR hypoechogenicity reflects an inclination for depression and anxiety characterized by the personality dimension neuroticism was not supported. However, this disposition may be present in a different state, such as stress.

Článek

Možnosti transkraniální sonografie na neuropsychiatrickém pomezí
[Use of transcranial sonography at neuro-psychiatry interface]

Česká a slovenská neurologie a neurochirurgie. 2016 ; 79 (6) : 649-654.

ISSN 1210-7859
Medvik
Zdroj

Využívání zobrazovacích metod je jeden z pilířů opětovného sbližování psychiatrie s neurologií. Transkraniální sonografie mozkové tkáně je metoda klinicky využívaná především v neurologii, svá první zjištění však přináší rovněž v oblasti duševních onemocnění. Sonografické nálezy se týkají zvláště struktur mozkového kmene. Snížená echogenita rafeální oblasti je spojena s unipolárními depresivními stavy, většinou organických depresivních poruch a některými úzkostnými poruchami, nevyskytuje se však u bipolární afektivní poruchy. Podle prvních výsledků může být rovněž markerem vyšší účinnosti serotonergních antidepresiv. Také hyperechogenita substantia nigra, typická pro Parkinsonovu chorobu, je zvýšeně nacházena u depresivních stavů a poukazuje na společné etiopatogenetické souvislosti. V psychiatrii navíc souvisí se závažností polékového extrapyramidového syndromu. Ověření a rozšíření těchto nálezů může poskytnout klinicky významné markery pro diskriminaci mezi unipolárními a bipolárními depresivními fázemi, pro cílenější volbu antidepresivní léčby a predikci rizika extrapyramidových nežádoucích účinků antipsychotik. Bližší přehled sonografických nálezů na neuropsychiatrickém pomezí přináší následující článek.

The use of neuroimaging methods is one of the pillars of re-convergence of neurology and psychiatry. Transcranial ultrasonography of the brainstem parenchyma is a method widely clinically used in neurology while it has also started to bear first fruit in the field of mental disorders. Sonographic imaging mainly concerns structures of the brainstem. Reduced echogenicity of the brainstem raphe is related to unipolar major depressive disorder, the majority of organic depressive disorders and several anxiety disorders but not bipolar affective disorder. According to initial results, this could be the marker of good efficacy of serotoninergic antidepressants. Hyperechogenicity of substantia nigra, typical for Parkinson’s disease, has also been frequently found in depressive states, and suggests shared etiopathogenic background. In addition, it is related to severity of medication-induced extrapyramidal syndrome in psychiatry. Verification and extension of these findings may provide clinically important markers for discrimination between unipolar and bipolar depression, a more personalized choice of an antidepressant and prediction of the risk of antipsychotic-induced extrapyramidal adverse effects. This article presents a detailed overview of brain sonographic findings when used at the interface between neurology and psychiatric border.

Článek

A Comprehensive Evaluation of Steroid Metabolism in Women with Intrahepatic Cholestasis of Pregnancy

PLoS One. 2016 ; 11 (8) : e0159203.

ISSN 1932-6203
Medvik
Zdroj

Intrahepatic cholestasis of pregnancy (ICP) is a common liver disorder, mostly occurring in the third trimester. ICP is defined as an elevation of serum bile acids, typically accompanied by pruritus and elevated activities of liver aminotransferases. ICP is caused by impaired biliary lipid secretion, in which endogenous steroids may play a key role. Although ICP is benign for the pregnant woman, it may be harmful for the fetus. We evaluated the differences between maternal circulating steroids measured by RIA (17-hydroxypregnenolone and its sulfate, 17-hydroxyprogesterone, and cortisol) and GC-MS (additional steroids), hepatic aminotransferases and bilirubin in women with ICP (n = 15, total bile acids (TBA) >8 μM) and corresponding controls (n = 17). An age-adjusted linear model, receiver-operating characteristics (ROC), and multivariate regression (a method of orthogonal projections to latent structure, OPLS) were used for data evaluation. While aminotransferases, conjugates of pregnanediols, 17-hydroxypregnenolone and 5β-androstane-3α,17β-diol were higher in ICP patients, 20α-dihydropregnenolone, 16α-hydroxy-steroids, sulfated 17-oxo-C19-steroids, and 5β-reduced steroids were lower. The OPLS model including steroids measured by GC-MS and RIA showed 93.3% sensitivity and 100% specificity, while the model including steroids measured by GC-MS in a single sample aliquot showed 93.3% sensitivity and 94.1% specificity. A composite index including ratios of sulfated 3α/β-hydroxy-5α/β-androstane-17-ones to conjugated 5α/β-pregnane-3α/β, 20α-diols discriminated with 93.3% specificity and 81.3% sensitivity (ROC analysis). These new data demonstrating altered steroidogenesis in ICP patients offer more detailed pathophysiological insights into the role of steroids in the development of ICP.

Článek

Transcranial sonography of brainstem structures in panic disorder

Psychiatry research. 2015 ; 234 (1) : 137-43. [pub] 20150908

Psychiatry Res
ISSN 1872-7123
Medvik
Zdroj

Panic disorder has been associated with altered serotonin metabolism in the brainstem raphe. The aim of study was to evaluate the BR echogenicity on transcranial sonography (TCS) in panic disorder. A total of 96 healthy volunteers were enrolled in the "derivation" cohort, and 26 healthy volunteers and 26 panic disorder patients were enrolled in the "validation" cohort. TCS echogenicity of brainstem raphe and substantia nigra was assessed on anonymized images visually and by means of digitized image analysis. Significantly reduced brainstem raphe echogenicity was detected more frequently in panic disorder patients than in controls using both visual (68% vs. 31%) and digitized image analysis (52% vs. 12%). The optimal cut-off value of digitized brainstem raphe echogenicity indicated the diagnosis of panic disorder with a sensitivity of 64% and a specificity of 73%, and corresponded to the 30th percentile in the derivation cohort. Reduced brainstem raphe echogenicity was associated with shorter treatment duration, and, by trend, lower severity of anxiety. No relationship was found between echogenicity of brainstem raphe or substantia nigra and age, gender, severity of panic disorder, or severity of depression. Patients with panic disorder exhibit changes of brainstem raphe on TCS suggesting an alteration of the central serotonergic system.