We have demonstrated previously that activation of either the ETA or ETB receptor can induce acute electrographic seizures following the intrahippocampal infusion of endothelin-1 (ET-1) in immature (P12) rats. We also demonstrated that activation of the ETA receptor is associated with marked focal ischemia, while activation of the ETB receptor is not. Exploring the mechanisms underlying seizures induced by these two ET-1 receptor interactions can potentially provide insight into how focal ischemia in immature animals produces seizures and whether ischemiarelated seizures differ from seizures not associated with ischemia. To explore these seizure mechanisms we used microdialysis to determine biomarkers associated with seizures in P12 rats following the intrahippocampal infusion of two different agents: (1) ET-1, which activates both the ETA and ETB receptors and causes focal ischemia and (2) Ala-ET-1, which selectively activates only the ETB receptor and does not cause ischemia. Our results show that seizures associated with combined ETA and ETB receptor activation (and ischemia) have a different temporal distribution and microdialysis profile from seizures associated with ETB activation alone (and without ischemia). Seizures with combined activation peak within the first hour after infusion and the microdialysis profile is characterized by a significant increase in the ratio of glutamic acid to GABA. By contrast, seizures with activation of only the ETB receptor peak in the second hour after infusion and microdialysis shows a significant increase in the ratio of leukotriene B4 to prostaglandin E2. These findings suggest that ischemia-related seizures in immature animals involve an imbalance of excitation and inhibition, while non-ischemiarelated seizures involve an inflammatory process resulting from an excess of leukotrienes.

• MeSH
• endotelin-1 toxicita   MeSH
• hipokampus účinky léků   metabolismus   MeSH
• ischemie mozku chemicky indukované   metabolismus   MeSH
• krysa rodu rattus MeSH
• potkani Wistar MeSH
• receptor endotelinu A metabolismus   MeSH
• receptor endotelinu B metabolismus   MeSH
• záchvaty chemicky indukované   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Renal medullary endothelin B receptors (ET(B)) mediate sodium excretion and blood pressure (BP) control. Several animal models of hypertension have impaired renal medullary ET(B) function. We found that 4-week high-caloric diet elevated systolic BP in Dahl salt-sensitive (Dahl S) rats (126+/-2 vs. 143+/-3 mm Hg, p<0.05). We hypothesized that renal medullary ET(B) function is dysfunctional in DS rats fed a high-caloric diet. We compared the diuretic and natriuretic response to intramedullary infusion of ET(B) agonist sarafotoxin 6c (S6c) in DS rats fed either a normal or high-caloric diet for 4 weeks. Urine was collected during intramedullary infusion of saline for baseline collection followed by intramedullary infusion of either saline or S6c. We first examined the ET(B) function in DS rats fed a normal diet. S6c increased urine flow (2.7+/-0.3 microl/min during baseline vs. 5.1+/-0.6 microl/min after S6c; p<0.05; n=5) and sodium excretion (0.28+/-0.05 vs. 0.81+/-0.17 micromol/min; p<0.05), suggesting that DS rats have renal medullary ET(B) function. However, DS rats fed a high-caloric diet displayed a significant increase in urine flow (2.7+/-0.4 vs. 4.2+/-0.4 microl/min, baseline vs. S6c infusion, respectively; p<0.05, n=6), but no significant change in sodium excretion in response to S6c (0.32+/-0.06 vs. 0.45+/-0.10 micromol/min). These data demonstrate that renal medullary ET(B) function is impaired in DS rats fed a high-caloric diet, which may be contributed to the elevation of blood pressure during high-caloric feeding in this model.

• MeSH
• dieta s vysokým obsahem tuků škodlivé účinky   MeSH
• dřeň ledvin účinky léků   metabolismus   MeSH
• hypertenze etiologie   metabolismus   MeSH
• krevní tlak účinky léků   fyziologie   MeSH
• krysa rodu rattus MeSH
• peptidy farmakologie   MeSH
• potkani inbrední Dahl MeSH
• přijímání potravy účinky léků   fyziologie   MeSH
• receptor endotelinu B agonisté   metabolismus   MeSH
• signální transdukce účinky léků   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Endothelin B (ET(B)) receptors present in abundance the central nervous system (CNS) have been shown to have significant implications in its development and neurogenesis. We have targeted ET(B) receptors stimulation using a highly specific agonist, IRL-1620, to treat CNS disorders. In a rat model of cerebral ischemia intravenous administration IRL-1620 significantly reduced infarct volume and improved neurological and motor functions compared to control. This improvement, in part, is due to an increase in neuroregeneration. We also investigated the role of IRL-1620 in animal models of Alzheimer's disease (AD). IRL-1620 improved learning and memory, reduced oxidative stress and increased VEGF and NGF in Abeta treated rats. IRL-1620 also improved learning and memory in an aged APP/PS1 transgenic mouse model of AD. These promising findings prompted us to initiate human studies. Successful chemistry, manufacturing and control along with mice, rat and dog toxicological studies led to completion of a human Phase I study in healthy volunteers. We found that a dose of 0.6 microg/kg of IRL-1620 can be safely administered, three times every four hours, without any adverse effect. A Phase II clinical study with IRL-1620 has been initiated in patients with cerebral ischemia and mild to moderate AD.

• MeSH
• endoteliny farmakologie   terapeutické užití   MeSH
• klinické zkoušky jako téma metody   MeSH
• lidé MeSH
• nemoci centrálního nervového systému farmakoterapie   metabolismus   MeSH
• neurodegenerativní nemoci farmakoterapie   metabolismus   MeSH
• oxidační stres účinky léků   fyziologie   MeSH
• peptidové fragmenty farmakologie   terapeutické užití   MeSH
• preklinické hodnocení léčiv metody   MeSH
• receptor endotelinu B agonisté   metabolismus   MeSH
• regenerace nervu účinky léků   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

The global epidemic of diabetes is of significant concern. Diabetes associated vascular disease signifies the principal cause of morbidity and mortality in diabetic patients. It is also the most rapidly increasing risk factor for cognitive impairment, a silent disease that causes loss of creativity, productivity, and quality of life. Small vessel disease in the cerebral vasculature plays a major role in the pathogenesis of cognitive impairment in diabetes. Endothelin system, including endothelin-1 (ET-1) and the receptors (ET(A) and ET(B)), is a likely candidate that may be involved in many aspects of the diabetes cerebrovascular disease. In this review, we took a brain-centric approach and discussed the role of the ET system in cerebrovascular and cognitive dysfunction in diabetes.

• MeSH
• antagonisté endotelinového receptoru A aplikace a dávkování   metabolismus   MeSH
• antagonisté endotelinového receptoru B aplikace a dávkování   metabolismus   MeSH
• endoteliny agonisté   antagonisté a inhibitory   metabolismus   MeSH
• komplikace diabetu farmakoterapie   metabolismus   MeSH
• lidé MeSH
• mozek účinky léků   metabolismus   MeSH
• mozkový krevní oběh účinky léků   fyziologie   MeSH
• receptor endotelinu A metabolismus   MeSH
• receptor endotelinu B metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

The endothelin axis (endothelins and their receptors) is strongly involved in physiological and pathological processes. ET-1 plays a crucial role in particular in tumor diseases. Endothelin-1 receptors (ET(A) and ET(B)) are deregulated and overexpressed in several tumors such as melanoma and glioma. We studied the binding of 24 monoclonal antibodies directed against human ET(B) receptors (hET(B)) to different melanoma cell lines. Few of these mAbs bound to all the melanoma cell lines. One of them, rendomab B49, bound to ET(B) receptors expressed at the surface of human glioma stem cells. More recently, we produced new antibodies directed against human ET(A) receptor (hET(A)). Several antibodies have been isolated and have been screened on different tumoral cells lines. As for the mAbs directed against the hET(B) receptor only some of new antibodies directed against ET(A) receptor are capable to bind the human tumoral cell lines. Rendomab A63 directed against hET(A) is one of them. We report the specificity and binding properties of these mAbs and consider their potential use in diagnosis by an in vivo imaging approach.

• MeSH
• antagonisté endotelinového receptoru A aplikace a dávkování   metabolismus   MeSH
• CHO buňky MeSH
• Cricetulus MeSH
• endotelin-1 genetika   metabolismus   MeSH
• křečci praví MeSH
• lidé MeSH
• monoklonální protilátky aplikace a dávkování   metabolismus   MeSH
• myši nahé MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• receptor endotelinu A genetika   metabolismus   MeSH
• receptor endotelinu B genetika   metabolismus   MeSH
• sekvence aminokyselin MeSH
• vazba proteinů fyziologie   MeSH
• xenogenní modely - testy antitumorózní aktivity metody   MeSH
• zvířata MeSH
• Check Tag
• křečci praví MeSH
• lidé MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Early addition of endothelin (ET) type A (ETA) receptor blockade to complex renin-angiotensin system (RAS) blockade has previously been shown to provide better renoprotection against progression of chronic kidney disease (CKD) in Ren-2 transgenic hypertensive rats (TGR) after 5/6 renal ablation (5/6 NX). In this study, we examined if additional protection is provided when ETA blockade is applied in rats with already developed CKD. METHODS: For complex RAS inhibition, an angiotensin-converting enzyme inhibitor along with angiotensin II type 1 receptor blocker was used. Alternatively, ETA receptor blocker was added to the RAS blockade. The treatments were initiated 6 weeks after 5/6 NX and the follow-up period was 50 weeks. RESULTS: When applied in established CKD, addition of ETA receptor blockade to the complex RAS blockade brought no further improvement of the survival rate (30% in both groups); surprisingly, aggravated albuminuria (588 ± 47 vs. 245 ± 38 mg/24 h, p < 0.05) did not reduce renal glomerular injury index (1.25 ± 0.29 vs. 1.44 ± 0.26), did not prevent the decrease in creatinine clearance (203 ± 21 vs. 253 ± 17 μl/min/100 g body weight), and did not attenuate cardiac hypertrophy to a greater extent than observed in 5/6 NX TGR treated with complex RAS blockade alone. CONCLUSIONS: When applied in the advanced phase of CKD, addition of ETA receptor blockade to the complex RAS blockade brings no further beneficial renoprotective effects on the CKD progression in 5/6 NX TGR, in addition to those seen with RAS blockade alone.

• MeSH
• albuminurie MeSH
• angiotensiny účinky léků   metabolismus   MeSH
• antagonisté endotelinového receptoru A farmakologie   MeSH
• blokátory receptoru 1 pro angiotenzin II farmakologie   MeSH
• chronická renální insuficience metabolismus   MeSH
• hodnoty glomerulární filtrace účinky léků   MeSH
• hypertenze MeSH
• indoly farmakologie   MeSH
• inhibitory ACE farmakologie   MeSH
• kardiomegalie MeSH
• kombinovaná farmakoterapie MeSH
• kreatinin metabolismus   MeSH
• krevní tlak účinky léků   MeSH
• krysa rodu rattus MeSH
• ledviny účinky léků   metabolismus   MeSH
• losartan farmakologie   MeSH
• míra přežití MeSH
• nefrektomie MeSH
• potkani Sprague-Dawley MeSH
• potkani transgenní MeSH
• progrese nemoci MeSH
• pyrrolidiny farmakologie   MeSH
• receptor endotelinu A účinky léků   metabolismus   MeSH
• receptor endotelinu B účinky léků   metabolismus   MeSH
• renin-angiotensin systém účinky léků   MeSH
• renin účinky léků   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

This study was designated to estimate protective role of ETA and ETB receptor antagonist against endothelin 1 (ET-1)-induced oxidative stress in lungs and determine whether these effects are mediated by nitric oxide (NO) synthase. Experiments were performed on Wistar rats divided into the following groups: I - saline (0.9 % NaCl); II - ET-1 (3 microg/kg b.w.), III - BQ123 (1 mg/kg b.w.) + ET-1 (3 microg/kg b.w.), IV - BQ788 (3 mg/kg b.w.) + ET-1 (3 microg/kg b.w.), V - N-nitro-L-arginine methyl ester (L-NAME) (5 mg/kg b.w.) + ET-1 (3 microg/kg b.w.). ETA and ETB receptor antagonists or L-NAME were administered 30 min before ET-1 injection. The levels of the following substances were measured in the lungs homogenates: thiobarbituric acid reactive substances (TBARS), hydrogen peroxide (H(2)O(2)), reduced glutathione (GSH) and tumor necrosis factor-alpha (TNF-alpha). The results showed that ET-1 significantly increased TBARS, H(2)O(2) (respectively: p<0.001, p<0.02) and TNF-alpha levels (p<0.02) and decreased the GSH level (p<0.01) vs. CONTROL GROUP: On the other hand, prior administration of ETA receptor blocker (BQ123) significantly attenuated TBARS (p<0.01), H(2)O(2) (p<0.02), TNF-alpha (p<0.02) and increased GSH (p<0.02) levels vs. ET-1. However, prior administration of ETB receptor blocker BQ788 did not cause significant changes in the: TBARS, H(2)O(2) and TNF-alpha (p>0.05) levels, but significantly increased the GSH level and GSH/GSSG ratio (p<0.05). Administration of L-NAME significantly attenuated TBARS (p<0.001), H(2)O(2) (p<0.05), TNF-alpha (p<0.01) and increased GSH (p<0.05) levels vs. ET-1. In conclusion, we demonstrated that ET-1 induced oxidative stress in the lungs is mediated by ETA receptors. ETA receptor blockage inhibited generation of free radicals and TNF-alpha and ameliorated antioxidant properties. Moreover, generation of reactive oxygen species is mediated by NOS in the lungs.

• MeSH
• antagonisté endotelinového receptoru farmakologie   terapeutické užití   MeSH
• cyklické peptidy farmakologie   terapeutické užití   MeSH
• endotelin-1 MeSH
• glutathion metabolismus   MeSH
• náhodné rozdělení MeSH
• NG-nitroargininmethylester farmakologie   terapeutické užití   MeSH
• oligopeptidy farmakologie   terapeutické užití   MeSH
• oxidační stres účinky léků   MeSH
• peroxid vodíku metabolismus   MeSH
• peroxidace lipidů účinky léků   MeSH
• piperidiny farmakologie   terapeutické užití   MeSH
• plíce účinky léků   metabolismus   MeSH
• plicní nemoci etiologie   metabolismus   prevence a kontrola   MeSH
• potkani Wistar MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• receptor endotelinu A metabolismus   MeSH
• receptor endotelinu B metabolismus   MeSH
• synthasa oxidu dusnatého metabolismus   MeSH
• TNF-alfa metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

The period around birth is a risky time for stroke in infants, which is associated with two major acute and subacute processes: anatomical damage and seizures. It is unclear as to what extent each of these processes independently contributes to poor outcome. Furthermore, it is unclear whether there is an interaction between the two processes - does seizure activity cause additional brain damage beyond that produced by ischemia and/or does brain damage foster seizures? The model of focal cerebral ischemia induced by the intrahippocampal infusion of endothelin-1 (ET-1) in 12-day-old rat was used to examine the role of the endothelin receptors in the development of focal ischemia, symptomatic acute seizures and neurodegeneration. ET-1 (40pmol/μl) was infused either alone or co-administered with selective antagonists of ETA (BQ123; 70nmol/μl) or ETB receptors (BQ788; 70nmol/1μl). Effects of activation of ETB receptors were studied using selective agonist 4-Ala-ET-1 (40pmol/1μl). Regional cerebral blood flow (rCBF) and tissue oxygenation (pO2) were measured in anesthetized animals with a Doppler-flowmeter and a pO2-sensor, respectively. Seizure development was assessed with video-EEG in freely moving rats. Controls received the corresponding volume of the appropriate vehicle (10mM PBS or 0.01% DMSO-PBS solution; pH7.4). The extent of hippocampal lesion was determined using FluoroJade B staining performed 24h after ET-1 infusion. Infusion of ET-1 or ET-1+ETB receptor antagonist reduced rCBF to ~25% and pO2 to ~10% for about 1.5h, whereas selective ETB agonist, ET-1+ETA antagonist and the PBS vehicle had only negligible effect on the rCBF and pO2 levels. Reduction of rCBF was associated with the development of lesion in the injected hippocampus. In all groups, except sham operated and PBS controls, epileptiform activity was observed after activation of the ETA or the ETB receptors. The data revealed a positive correlation between the severity of morphological damage and all the measured seizure parameters (seizure frequency, average and total seizure duration) in the ET-1 group. In addition, the severity of morphological damage positively correlated with the average seizure duration in animals after infusion of ET-1+ETA receptor antagonist or after infusion of ET-1+ETB receptor antagonist. Our results indicate that the activation of ETA receptors is crucial for ischemia development, however either ETA or ETB receptors mediate the development of seizures following the application of ET-1 in immature rats. The dissociation between the ischemic-producing and seizure-producing processes suggests that damage is not necessary to induce seizures, although it may exacerbate them.

• MeSH
• elektroencefalografie * účinky léků   MeSH
• endotelin-1 aplikace a dávkování   toxicita   MeSH
• hipokampus účinky léků   metabolismus   MeSH
• injekce intraventrikulární MeSH
• krysa rodu rattus MeSH
• potkani Wistar MeSH
• receptor endotelinu A agonisté   metabolismus   MeSH
• receptor endotelinu B agonisté   metabolismus   MeSH
• záchvaty chemicky indukované   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Effects of ETB receptor stimulation and its subcellular pathways were evaluated in carbachol pre-contracted rabbit iris sphincter muscles (n=51). ETB stimulation with sarafotoxin (SRTX-c; 10-10-10-6 M) was tested in the absence (n=7) or presence of 10-5 M of: BQ-788 (ETB2 receptor antagonist; n=6), L-NA (NOS inhibitor; n=7) or indomethacin (cyclooxygenase inhibitor; n=10). Effects of ETB stimulation by endothelin-1 (ET-1; 10-10– 10-7 M) in the presence of an ETA receptor antagonist (BQ-123; 10-5 M; n=7) and of ETB1 stimulation by IRL-1620 (10-10–10-7 M; n=7) were also tested. Finally, the effects of SRTX-c (10-9–10-7 M) in electric field stimulation (EFS) contraction were evaluated (n=7). ETB receptor stimulation by SRTX-c or ET-1 in presence of BQ-123 promoted a concentration-dependent relaxation of the rabbit iris sphincter muscle by 10.8±2.0 % and 9.4±1.8 %, respectively. This effect was blocked by BQ-788 (-2.3±2.0 %), L-NA (4.5±2.3 %) or indomethacin (2.3±2.9 %). Selective ETB1 stimulation by IRL-1620 did not relax the iris sphincter muscle (0.9±5.4 %). EFS elicited contraction was not altered by SRTX-c. In conclusion, ETB receptor stimulation relaxes the carbachol precontracted iris sphincter muscle, an effect that is mediated by the ETB2 receptor subtype, through NO and the release of prostaglandins.

• MeSH
• cyklooxygenasy metabolismus   MeSH
• elektrická stimulace MeSH
• endotelin-1 metabolismus   MeSH
• endoteliny farmakologie   MeSH
• financování organizované MeSH
• hladké svalstvo metabolismus   účinky léků   MeSH
• indomethacin farmakologie   MeSH
• inhibitory enzymů MeSH
• iris metabolismus   účinky léků   MeSH
• karbachol farmakologie   MeSH
• králíci MeSH
• nitroarginin farmakologie   MeSH
• oligopeptidy farmakologie   MeSH
• oxid dusnatý metabolismus   MeSH
• peptidové fragmenty farmakologie   MeSH
• peptidy farmakologie   MeSH
• piperidiny farmakologie   MeSH
• prostaglandiny metabolismus   MeSH
• receptor endotelinu A metabolismus   MeSH
• receptor endotelinu B agonisté   metabolismus   MeSH
• relaxace svalu účinky léků   MeSH
• synthasa oxidu dusnatého antagonisté a inhibitory   metabolismus   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• králíci MeSH
• mužské pohlaví MeSH
• zvířata MeSH