endothelin-1 and Fever

Bai-Hu-Tang (BHT) is traditionally used to treat human and animal fever syndrome with four symptoms: large and vigorous pulse, large thirst, high sweat, and high heat.. To investigate the mechanism of vasodilation regulation of Bai-Hu-Tang in primary vascular endothelial cells stimulated by lipopolysaccharide (LPS).. A hydrophilic concentrate of BHT was prepared, and the main components of mangiferin and timosaponin BⅡ were determined by HLPC analysis. The rabbit fever model was constructed by intravenous injection of LPS (15 μg/kg body weight), and BHT was gavaged to treat febrile rabbits. After treatment for 6 h, animal peripheral blood was collected, and serum was isolated for endothelin-1 (ET-1) and nitric oxide (NO) assays. Rabbit vascular endothelial cells (RVECs) were isolated and stimulated with 1 μg/mL LPS, and then inflammatory cells were treated with 125 or 250 μg/mL BHT for 24 h. The supernatant cytokines TNF-ɑ, IL-1β, IL-6, and ET-1 were detected by ELISA kits. Gene expression levels of endothelin receptor type B (ET. Animal experiments demonstrated that BHT significantly restored ET-1 and NO in animal peripheral blood, which were disordered in LPS-induced fever rabbits. Moreover, a cytotoxicity assay demonstrated that BHT ≤700 μg/mL is innoxious to RVECs. BHT significantly repressed cellular TNF-α, IL-1β, and ET-1, which were originally elevated by LPS in RVECs. Meanwhile, BHT elevated the gene expression level of the ET. BHT can inhibit excessive ET-1 secretion induced by LPS in vascular endothelial cells and activate the classic ET-1 signalling pathway to promote NO production, which may facilitate vasodilation of smooth muscle cells.

Topics: Animals; Cytokines; Drugs, Chinese Herbal; Endothelial Cells; Endothelin-1; Fever; Gene Expression Regulation; Lipopolysaccharides; Phytotherapy; Rabbits; Random Allocation; RNA, Messenger

Sex differences in the immune response can also affect the febrile response, particularly the fever induced by lipopolysaccharide (LPS). However, other pathogen-associated molecular patterns, such as zymosan A (Zym) and polyinosinic-polycytidylic acid (Poly I:C), also induce fever in male rats with a different time course of cytokine release and different mediators such as endothelin-1 (ET-1). This study investigated whether female sex hormones affect Zym- and Poly I:C-induced fever and the involvement of ET-1 in this response. The fever that was induced by Zym and Poly I:C was higher in ovariectomized (OVX) female rats compared with sham-operated female rats. Estrogen replacement in OVX females reduced Zym- and Poly I:C-induced fever. The ET

Topics: Animals; Endothelin-1; Female; Fever; Gonadal Steroid Hormones; Injections, Intraventricular; Male; Ovariectomy; Poly I-C; Rats; Rats, Wistar; Zymosan

Topics: Analgesics, Opioid; Animals; Corticotropin-Releasing Hormone; Cytokines; Endothelin-1; Female; Fever; Hypothalamus; Lipopolysaccharides; Ovariectomy; Prostaglandins; RANK Ligand; Rats; Rats, Wistar; Substance P

This study aims to explore the contribution of endocannabinoids on the cascade of mediators involved in LPS-induced fever and to verify the participation of prostaglandins and endogenous opioids in fever induced by anandamide (AEA). Body temperature (Tc) of male Wistar rats was recorded over 6h, using a thermistor probe. Cerebrospinal fluid concentration of PGE2 and β-endorphin were measured by ELISA after the administration of AEA. Intracerebroventricular administration of the CB1 receptor antagonist AM251 (5μg, i.c.v.), reduced the fever induced by IL-1β (3ng, i.c.v.), TNF-α (250ng, i.c.v.), IL-6 (300ng, i.c.v.), corticotrophin release factor (CRH; 2.5μg, i.c.v.) and endothelin (ET)-1 (1pmol, i.c.v.), but not the fever induced by PGE2 (250ng, i.c.v.) or PGF2α (250ng, i.c.v.). Systemic administration of indomethacin (2mgkg(-1), i.p.) or celecoxib (5mgkg(-1), p.o.) reduced the fever induced by AEA (1μg, i.c.v.), while naloxone (1mgkg(-1), s.c.) abolished it. The increases of PGE2 and β-endorphin concentration in the CSF induced by AEA were abolished by the pretreatment of rats with AM251. These results suggest that endocannabinoids are intrinsically involved in the pyretic activity of cytokines (IL-1β, TNF-α, IL-6), CRH and ET-1 but not the PGE2 or PGF2α induced fevers. However, anandamide via CB1 receptor activation induces fever that is dependent on the synthesis of prostaglandin and opioids.

Topics: Animals; Arachidonic Acids; beta-Endorphin; Body Temperature; Corticotropin-Releasing Hormone; Cytokines; Endocannabinoids; Endothelin-1; Fever; Interleukin-1beta; Interleukin-6; Male; Naloxone; Narcotic Antagonists; Piperidines; Polyunsaturated Alkamides; Prostaglandins; Pyrazoles; Rats; Rats, Wistar; Receptor, Cannabinoid, CB1; Tumor Necrosis Factor-alpha

Recent literature has revealed that centrally generated prostaglandins participate in the febrile response in zymosan-induced arthritis in rats. However, it is not clear whether other centrally acting pyrogenic mediators such as cytokines, endothelins (ETs), and the corticotropin-releasing factor (CRF) contribute to the febrile response in this model. In the present study, rats were pretreated with intracerebroventricular (i.c.v.) injections of soluble TNF receptor I (sTNFRI), recombinant IL-1 receptor antagonist (IL-1ra), anti-rat IL-6 monoclonal antibody (AbIL-6), α-helical CRF9-41 (a nonselective CRF1/CRF2 receptor antagonist), BQ-123 (an ETA receptor antagonist), BQ-788 (an ETB receptor antagonist), and artificial cerebrospinal fluid (aCSF, control) prior to an intra-articular zymosan (4 mg) injection. Rectal temperatures were measured with a telethermometer. The administration of IL-1ra (200 µg), sTNFRI (500 ng), and AbIL-6 (5 µg) attenuated body temperature elevations after a zymosan injection. The administration of BQ-788 (3 pmol), BQ-123 (3 pmol), and α-helical CRF9-41 (25 µg) did not affect the zymosan-induced febrile response. All the compounds used to pretreat the animals did not significantly alter their basal body temperatures. Together, the results here demonstrate that the febrile response in zymosan-induced arthritis in rats depends on the centrally acting pyrogenic cytokines TNF-α, IL-1β, and IL-6, but does not depend on either CRF or ET-1.

Topics: Animals; Arthritis; Body Temperature; Corticotropin-Releasing Hormone; Cytokines; Disease Models, Animal; Endothelin-1; Fever; Hyperalgesia; Male; Rats, Wistar; Zymosan

Bacterial lipopolysaccharide (LPS) induces fever through two parallel pathways; one, prostaglandin (PG)-dependent and the other, PG-independent and involving endothelin-1 (ET-1). For a better understanding of the mechanisms by which dipyrone exerts antipyresis, we have investigated its effects on fever and changes in PGE(2) content in plasma, CSF and hypothalamus induced by either LPS or ET-1.. Rats were given (i.p.) dipyrone (120 mg·kg(-1)) or indomethacin (2 mg·kg(-1)) 30 min before injection of LPS (5 µg·kg(-1), i.v.) or ET-1 (1 pmol, i.c.v.). Rectal temperature was measured by tele-thermometry. PGE(2) levels were determined in the plasma, CSF and hypothalamus by elisa.. LPS or ET-1 induced fever and increased CSF and hypothalamic PGE(2) levels. Two hours after LPS, indomethacin reduced CSF and hypothalamic PGE(2) but did not inhibit fever, while at 3 h it reduced all three parameters. Three hours after ET-1, indomethacin inhibited the increase in CSF and hypothalamic PGE(2) levels but did not affect fever. Dipyrone abolished both the fever and the increased CSF PGE(2) levels induced by LPS or ET-1 but did not affect the increased hypothalamic PGE(2) levels. Dipyrone also reduced the increase in the venous plasma PGE(2) concentration induced by LPS.. These findings confirm that PGE(2) does not play a relevant role in ET-1-induced fever. They also demonstrate for the first time that the antipyretic effect of dipyrone was not mechanistically linked to the inhibition of hypothalamic PGE(2) synthesis.

Topics: Animals; Antipyretics; Body Temperature; Cyclooxygenase Inhibitors; Dinoprostone; Dipyrone; Endothelin-1; Escherichia coli; Fever; Hypothalamus; Indomethacin; Lipopolysaccharides; Male; Pyrogens; Rats; Rats, Wistar

The fever induced by lipopolysaccharide (LPS) depends on both prostaglandin-dependent and -independent pathways. One of the prostaglandin-independent pathways is sequentially orchestrated by pre-formed pyrogenic factor derived from LPS-stimulated macrophages (PFPF), corticotrophin releasing factor (CRF), endothelin-1 (ET-1) and interleukin-1 (IL-1). As macrophage-inflammatory-protein (MIP)-1 alpha (synonym CCL3) also induces a prostaglandin independent fever, the aim of the present study was to investigate a possible participation of CCL3/MIP-1 alpha within the prostaglandin-independent pathway of LPS-induced fever which depends on PFPF, CRF and ET-1. Therefore, rats received intracerebroventricular (i.c.v.) pre-treatment with anti-CCL3 monoclonal antibody (1 and 5 ng) at 1 h and 15 min before injection of LPS (lipopolysaccharide from E. coli; 5, 50 or 100 microg kg(-1), i.v.) or CCL3/MIP-1 alpha (500 pg, i.c.v.). Both doses of anti-CCL3 did not change the basal temperature but abolished the fever induced by CCL3/MIP-1 alpha. When given at the higher dose, anti-CCL3 did not influence the fever induced by i.v. injection of different doses of LPS, or i.c.v. administration of PFPF (200 ng), CRF (3 microg) or ET-1 (1 pmol). Bosentan, a non-selective ET(A/B) receptors antagonist (10 microg kg(-1), i.v.), reduced the fever induced by LPS but not that induced by CCL3/MIP-1 alpha. In contrast, alpha-helical CRF(9-41) (a non-selective CRF R1/R2 receptor antagonist; 25 microg injected i.c.v.) reduced CCL3/MIP-1 alpha-induced fever. In conclusion, the present results indicate that: i) CCL3/MIP-1 alpha is not an endogenous mediator of LPS-induced fever; ii) it is even not involved in the prostaglandin-independent pathway of the LPS-fever cascade and iii) its pyrogenic activity depends on synthesis/release of CRF.

Topics: Animals; Antibodies, Monoclonal; Antihypertensive Agents; Bosentan; Chemokine CCL3; Corticotropin-Releasing Hormone; Drug Interactions; Endothelin-1; Fever; Injections, Intraventricular; Lipopolysaccharides; Macrophages; Male; Mice; Peptide Fragments; Rats; Rats, Wistar; Recombinant Proteins; Sulfonamides

The intracerebroventricular injection of endothelin-1 (ET-1) induces fever and increases PG levels in the cerebrospinal fluid of rats. Likewise, the injection of IL-1 into the preoptic area (POA) of the rat hypothalamus causes both fever and increased PG production. In this study, we conducted in vivo and in vitro experiments in the rat to investigate 1) the hypothalamic region involved in ET-1-induced fever and PG biosynthesis and 2) whether hypothalamic IL-1 plays a role as a mediator of the above ET-1 activities. One hundred femtomoles of ET-1 increased body temperature when injected in the POA of conscious Wistar rats; this effect was significantly counteracted by the coinjection of 600 pmol IL-1 receptor antagonist (IL-1ra). In experiments on rat hypothalamic explants, 100 nM ET-1 caused a significant increase in PGE2 production and release from the whole hypothalamus and from the isolated POA, but not from the retrochiasmatic region, in 1-h incubations. Six nanomoles of IL-1ra or 10 nM of a cell-permeable interleukin-1 converting enzyme inhibitor completely counteracted the effect of ET-1 on PGE2 release from the POA. One hundred nanomoles ET-1 also caused a significant increase in IL-1beta immunoreactivity released into the bath solution of hypothalamic explants after 1 h of incubation, although during such time ET-1 failed to modify the gene expression of IL-1beta and other pyrogenic cytokines within the hypothalamus. In conclusion, our results show that ET-1 increases IL-1 production in the POA, and this effect appears to be correlated to ET-1-induced fever in vivo, as well as to PG production in vitro.

Topics: Animals; Body Temperature; Dinoprostone; Endothelin-1; Fever; Gene Expression; Hypothalamus; Interleukin 1 Receptor Antagonist Protein; Interleukin-1; Interleukin-6; Lipopolysaccharides; Male; Preoptic Area; Rats; Rats, Wistar; Serpins; Sialoglycoproteins; Viral Proteins

This study evaluates the antipyretic activity of nimesulide, a cyclooxygenase (COX-2) selective inhibitor in rats. The effects of nimesulide on lipopolysaccharide (LPS)-induced cerebrospinal prostaglandin E(2) (PGE(2)) and prostaglandin F(2alpha) (PGF(2alpha)) and on plasma tumor necrosis factor-alpha (TNF-alpha) levels were also evaluated. Male Wistar rats received an i.p. injection of LPS, or i.c.v. injections of interleukin-1beta (IL-1beta), interleukin-6 (IL-6), TNF-alpha, macrophage inflammatory protein-1alpha (MIP-1alpha), arachidonic acid, PGE(2), PGF(2alpha), corticotrophin-releasing factor (CRF) or endothelin-1 (ET-1). Nimesulide or indomethacin administered i.p 30 min prior LPS, IL-1beta, IL-6, TNF-alpha or arachidonic acid reduced the febrile response and PGE(2) or PGF(2alpha) levels in LPS-febrile rats but did not modify PGE(2)-induced fever. Nimesulide, but not indomethacin, reduced the fever induced by MIP-1alpha, PGF(2alpha), CRF or ET-1. Plasma TNF-alpha levels in LPS-treated rats were also reduced by nimesulide. These findings confirm that the antipyretic effect of nimesulide differs from the antipyretic scenario with the non-selective cyclooxygenase blocker indomethacin. Additional mechanisms, including inhibition of increased plasma TNF-alpha, may contribute to its antipyretic activity in rats.

Topics: Analgesics, Non-Narcotic; Animals; Arachidonic Acid; Body Temperature; Chemokine CCL3; Chemokine CCL4; Corticotropin-Releasing Hormone; Cyclooxygenase Inhibitors; Dinoprost; Dinoprostone; Dose-Response Relationship, Drug; Endothelin-1; Fever; Indomethacin; Injections, Intraperitoneal; Injections, Intraventricular; Interleukin-1beta; Interleukin-6; Lipopolysaccharides; Macrophage Inflammatory Proteins; Male; Rats; Rats, Wistar; Sulfonamides; Time Factors; Tumor Necrosis Factor-alpha

It was previously shown that sustained fever can be induced in rats by central injection of endothelin-1 (ET-1). This peptide appears to participate in the mechanism(s) of LPS-induced fever, which is reduced by pretreatments with ET(B) receptor antagonists. In this study, we compared the effects of a nonselective cyclooxygenase (COX) inhibitor, indomethacin, with those of two selective COX-2 inhibitors, celecoxib and lumiracoxib, on ET-1-induced fever in rats. Fever induced in conscious animals by ET-1 (1 pmol icv) or LPS (5 mug/kg iv) was prevented by pretreatments with celecoxib (5 and 10 mg/kg) or lumiracoxib (5 mg/kg) given by oral gavage 1 h before stimuli. Lower doses of celecoxib had partial (2.5 mg/kg) or no effect (1 mg/kg). Indomethacin (2 mg/kg ip) partially inhibited fever induced by LPS but had no effect on ET-1-induced fever. The levels of PGE(2) and PGF(2alpha) in the cerebrospinal fluid (CSF) of pentobarbital sodium-anesthetized rats were significantly increased 3 h after the injection of LPS or ET-1. The latter increase was abolished by celecoxib at all tested doses and by indomethacin. In conclusion, selective COX-2 inhibitors were able to prevent ET-1-induced fever, indicating a role for COX-2 in this phenomenon. However, the fact that reduced CSF PG levels obtained with indomethacin and a low dose of celecoxib are not accompanied by changes in fever induced by ET-1, along with the lack of inhibitory effects of indomethacin on ET-1 fever, suggests that the latter might also involve COX-2-independent mechanisms.

Topics: Animals; Celecoxib; Cyclooxygenase Inhibitors; Diclofenac; Dinoprost; Dinoprostone; Dose-Response Relationship, Drug; Endothelin-1; Fever; Indomethacin; Injections, Intraperitoneal; Injections, Intraventricular; Intubation, Gastrointestinal; Lipopolysaccharides; Male; Organic Chemicals; Pyrazoles; Rats; Rats, Wistar; Sulfonamides

Fever induced by E. coli lipopolysaccharide (LPS) in rats is substantially reduced by blockade of central endothelin ET(B) receptors. This study explores the role of endothelin-1 as a central mediator of fever in rats, by investigating the effect of a pyrogenic dose of LPS on the levels of big endothelin-1 and endothelin-1 in the cerebrospinal fluid (CSF) and endothelin-1 in the plasma. We further assessed whether the increase in body temperature caused by central injection of endothelin-1 constitutes solely a hyperthermia or a true integrated febrile response. LPS (5 mug kg(-1), i.v.) induced fever which peaked at 1.16 +/- 0.24 degrees C within 2 h and remained stable up to 5 h. CSF levels of immunoreactive (ir) big endothelin-1 decreased to undetectable levels at 3 h after LPS, returning only partially at 5 h post-injection. CSF ir-endothelin-1 levels were undetectable in saline-treated animals, but reached 21.9 +/- 5.2 fmol ml(-1) at 3 h after LPS treatment. Plasma ir-endothelin-1 levels were unchanged after saline or LPS. Central injection of endothelin-1 (1 pmol, i.c.v.) caused long-lasting increases in body temperature (0.81 +/- 0.17 degrees C, 3 h), but simultaneously decreased tail skin temperature (-1.10 +/- 0.26 degrees C), indicating cutaneous vasoconstriction. Moreover, endothelin-1 induced fever (1.0 +/- 0.3 degrees C, 3 h) when injected into the preoptic area of the anterior hypothalamus (100 fmol), but not i.v. (1 or 10 pmol). These data suggest that endothelin-1 is produced in the brain and acts centrally as a mediator of LPS-induced fever.

Topics: Animals; Antihypertensive Agents; Body Temperature; Endothelin-1; Fever; Injections, Intravenous; Lipopolysaccharides; Male; Microinjections; Oligopeptides; Piperidines; Preoptic Area; Rats; Rats, Wistar; Skin Temperature

1. Inflammatory bowel disease (IBD) is a condition that involves proinflammatory cytokines such as interleukins 1beta and 6 (ILs). In this disease, it has been shown that an abnormal microcirculatory system is implicated. 2. Therefore, the effects of in vivo treatment for three days with interleukins 1beta and 6 were investigated on rat isolated mesenteric vascular bed (MVB). 3. A significant concentration-dependent increase in vascular response to noradrenaline (NA) was found, with a significant difference in Emax between control (93.01 +/- 16.78 mmHg) and treated preparations (137.91 +/- 5.20 mmHg). Endothelin-1(ET-1) induced a significantly greater increase of perfusion pressure in treated rats in comparison with control rats at the highest concentration used (0.1 microm). 4. The concentration-dependent decrease of perfusion pressure induced by acetylcholine (ACh) in MVB precontracted with NA was significantly reduced in specimens from treated rats in comparison with control rats, with a significant difference in Emax between control and treated preparations. 5. Perivascular nerve stimulation (PNS) evoked contractions with no difference between treatments. Similarly, no difference in relaxant effect was found after PNS in specimens precontracted with NA, in the presence of guanethidine. 6. These findings indicate that the precocious inflammation acts only at postsynaptic level, facilitating vascular contraction. These data seem to support the hypothesis that vascular dysfunction caused by overproduction of ILs may contribute, among other immunological factors, to vasculitis in IBD that leads to intestinal ischaemia through vasoconstriction.

Topics: Acetylcholine; Animals; Arginine; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Synergism; Electric Stimulation; Endothelin-1; Fever; Guanethidine; Inflammation; Interleukin-1; Interleukin-6; Intestinal Mucosa; Isomerism; Isoproterenol; Male; Mesenteric Arteries; NG-Nitroarginine Methyl Ester; Norepinephrine; Perfusion; Rats; Rats, Sprague-Dawley; Sumatriptan; Time Factors; Vascular Resistance; Vasoconstriction; Vasodilation

To analyze the effect of hyperthermia on the vascular response, the isometric response of isolated rabbit femoral artery segments was recorded at 37 degreesC and hyperthermia (41 and 44 degreesC). Contraction to potassium (5 x 10(-3)-5 x 10(-2) M) was significantly greater at 41 and 44 than at 37 degreesC and increased by inhibition of nitric oxide (NO) synthesis with Nomega-nitro-L-arginine (L-NNA; 10(-4) M) or endothelium removal at 37 degreesC but not at 41 or 44 degreesC. Norepinephrine (10(-9)-10(-4) M) produced a concentration-dependent contraction greater at 41 or 44 than at 37 degreesC and not modified by endothelium removal or L-NNA at either temperature. Phenylephrine (10(-9)-10(-4) M) produced a contraction increased by warming to 44 degreesC but not to 41 degreesC. The specific alpha2-adrenoceptor agonist BHT-920 produced a weak contraction, reduced by the alpha1-adrenoceptor antagonist prazosin (10(-6) M) and increased at 44 degreesC but not at 41 degreesC. The concentration-dependent contraction to endothelin-1 (ET-1; 10(-11)-10(-7) M) was increased by warming to 41 and 44 degreesC and by endothelium removal or L-NNA at 37 degreesC but not at 41 or 44 degreesC. Response to ET-1 was reduced by endothelin ETA-receptor antagonist BQ-123 (10(-5) M) and ETB-receptor antagonist BQ-788 (10(-5) M). In arteries precontracted with ET-1 (10(-8)-3 x 10(-8) M), relaxation to sodium nitroprusside (10(-8)-10(-4) M) was increased at 41 and 44 degreesC vs. at 37 degreesC, but that of ACh (10(-8)-10(-4) M) or adenosine (10(-8)-10(-4) M) was not different at all temperatures studied. Relaxation to ACh, but not adenosine, was reduced similarly by L-NNA at all temperatures studied. These results suggest hyperthermia in muscular arteries may inhibit production of, and increase dilatation to, NO, resulting in unchanged relaxation to ACh and increased constriction to KCl and ET-1, and may increase constriction to stimulation of alpha1-adrenoceptors by NO-independent mechanisms.

Topics: Acetylcholine; Adenosine; Animals; Azepines; Endothelin Receptor Antagonists; Endothelin-1; Femoral Artery; Fever; In Vitro Techniques; Nitric Oxide; Nitroarginine; Nitroprusside; Norepinephrine; Potassium Chloride; Rabbits; Receptors, Adrenergic, alpha; Vasoconstriction; Vasodilation