Molecular mechanisms for sweet-suppressing effect of gymnemic acids.

Gymnemic acids are triterpene glycosides that selectively suppress taste responses to various sweet substances in humans but not in mice. This sweet-suppressing effect of gymnemic acids is diminished by rinsing the tongue with γ-cyclodextrin (γ-CD). However, little is known about the molecular mechanisms underlying the sweet-suppressing effect of gymnemic acids and the interaction between gymnemic acids versus sweet taste receptor and/or γ-CD.

Chronic restraint stress in rats suppresses sweet and umami taste responses and lingual expression of T1R3 mRNA.

Effects of chronic restraint stress on the taste responses to five basic taste qualities were investigated electrophysiologically in the rat chorda tympani. In addition, the mRNA expression for T1R3, the common G-protein-coupled receptor (GPCR) for sweet and umami tastes, was studied quantitatively by RT-PCR after such stress. Rats were restrained in a small cylindrical restrainer made of steel wire for 8h daily for 14 successive days.

Induction of salivary kallikreins by the diet containing a sweet-suppressive peptide, gurmarin, in the rat.

Gymnema sylvestre (gymnema) contains gurmarin that selectively inhibits responses to sweet substances in rodents. The present study investigated possible interaction between gurmarin and the submandibular saliva in rats fed diet containing gymnema. Electrophoretic analyses demonstrated that relative amounts of two proteins in the saliva clearly increased in rats fed the gymnema diet.

Systemic administration of polymyxin B induces hypothermia in rats via an inhibitory effect on metabolic rate.

Polymyxin B, a cyclic cationic polypeptide antibiotic, binds to the lipid A of bacterial endotoxin (lipopolysaccharide; LPS) to inhibit LPS-induced fever. On the basis of a casual observation, we hypothesised that in rats (unlike in rabbits and goats), intravenous (i.v.

Effect of natriuretic peptide receptor antagonist on lipopolysaccharide-induced fever in rats: is natriuretic peptide an endogenous antipyretic?

We investigated whether natriuretic peptide (NP) acts as an endogenous antipyretic inside and/or outside the blood-brain barrier in rats made febrile by systemic administration of bacterial endotoxin (lipopolysaccharide; LPS). Intravenous (i.v.

Effects of central injection of angiotensin-converting-enzyme inhibitor and angiotensin type 1 receptor antagonist on the brain NF-kappaB and AP-1 activities of rats given LPS.

Angiotensin II (ANG II) activation of the angiotensin type 1 (AT1) receptor facilitates the production of brain interleukin-1beta (IL-1beta) and contributes to the induction of the fever following the intracerebroventricular (i.c.v.

Interaction of gymnemic acid with cyclodextrins analyzed by isothermal titration calorimetry, NMR and dynamic light scattering.

The physiological phenomenon that the antisweet taste effect of gymnemic acid (GA) is diminished by application of gamma-cyclodextrin (gamma-CD) to the mouth was evaluated at the molecular level using isothermal titration calorimetry, NMR and dynamic light scattering. These analyses showed that GA specifically binds to gamma-CD. Thermodynamic analysis using isothermal titration calorimetry revealed that the association constant of GA and gamma-CD is 10(5)-10(6) m(-1) with favorable enthalpy and entropy changes.

Gymnemic acids inhibit rabbit glyceraldehyde-3-phosphate dehydrogenase and induce a smearing of its electrophoretic band and dephosphorylation.

Gymnemic acids (GA) inhibited rabbit muscle glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity. Binding of GA to GAPDH was observed by surface plasmon resonance measurement. Incubation of GAPDH with GA induced a smearing of the GAPDH band in SDS-PAGE.

Systemic administration of lipopolysaccharide upregulates angiotensin II expression in rat renal tubules: immunohistochemical and ELISA studies.

We investigated whether angiotensin II (AII) peptide is induced in the rat kidney under endotoxemic conditions. Immunohistochemistry revealed strong AII-like immunoreactivity in the renal tubules of rats given high-dose lipopolysaccharide (LPS; 1000 microg/kg) intraperitoneally (i.p.

Endogenous cryogens existing in the blood of a hypothermic patient.

We treated a young female patient who suffered from severe hypothermia. The etiology of the hypothermia was not identified, though various medical examinations were performed. Intraperitoneal (i.

Angiotensin II: its effects on fever and hypothermia in systemic inflammation.

Angiotensin II (ANG II), a bioactive peptide that plays important roles in blood-pressure and body-fluid regulation, has recently been reported to be involved in normal thermoregulation and fever. In the case of thermoregulation, ANG II lowers body temperature when administered centrally or systemically (i.e.

The effect of central injection of angiotensin-converting enzyme inhibitor and the angiotensin type 1 receptor antagonist on the induction by lipopolysaccharide of fever and brain interleukin-1beta response in rats.

We recently reported an involvement of peripheral angiotensin II (ANG II) in the development of both the fever and the peripheral interleukin (IL)-1beta production induced in rats by a systemic injection of lipopolysaccharide (LPS). The present study was performed to investigate whether brain ANG II contributes to the fever and IL-1beta production in the rat brain induced by i.c.

6-Formylpterin protects retinal neurons from transient ischemia-reperfusion injury in rats: a morphological and immunohistochemical study.

Neuroprotective effects of 6-formylpterin (6FP) on transient retinal ischemia-reperfusion injury were evaluated in rats by means of counting the number of retinal ganglion cells, measuring the thicknesses of the inner plexiform and inner nuclear layers, and by immunohistochemical detection of apoptotic cells in the retina. Sixty-one Sprague-Dawley rats (12 weeks, male, 295-330 g) were subjected to transient retinal ischemia-reperfusion by elevated intra-ocular pressure (80 mmHg for 60 min). Intraperitoneal injection of 6FP (3.

Differential gurmarin suppression of sweet taste responses in rat solitary nucleus neurons.

We examined the effect of the sweet transduction blocker gurmarin on taste responses recorded from neurons in the rat solitary nucleus (NST) to determine how gurmarin sensitivity is distributed across neuronal type. Initially, responses evoked by washing the anterior tongue and palate with 0.5 M sucrose, 0.

ANG II is involved in the LPS-induced production of proinflammatory cytokines in dehydrated rats.

We have previously reported results that led us to speculate that ANG II is involved in the LPS-induced production of proinflammatory cytokines, especially under dehydrated conditions. To test this possibility, in this study we examined the effects of an angiotensin-converting enzyme (ACE) inhibitor and an antagonist of the type-1 ANG II receptor (AT(1) receptor) on the LPS-induced production of the proinflammatory cytokines IL-1 and IL-6 in dehydrated rats. A single intravenous injection of LPS induced a marked increase in the expression of IL-1beta mRNA in the liver, an effect that was significantly attenuated by pretreatment with the ACE inhibitor.