Effect of Hafnia alvei on Morphophysiologic Parameters and Gut Microbiota of Mice with Inherited Type 2 Diabetes Mellitus.

Inbred mouse strains KK.Cg-a/a and KK.Cg-Ay/a known as genetic models of type 2 diabetes mellitus significantly surpassed the control strain C57BL/6J in the body weight, relative weight of extractable fat, and basal blood glucose levels.

The Role of K Channels in Atrial Fibrillation.

This manuscript explores the intricate role of acetylcholine-activated inward rectifier potassium (K) channels in the pathogenesis of atrial fibrillation (AF), a common cardiac arrhythmia. It delves into the molecular and cellular mechanisms that underpin AF, emphasizing the vital function of K channels in modulating the atrial action potential and facilitating arrhythmogenic conditions. This study underscores the dual nature of K activation and its genetic regulation, revealing that specific variations in potassium channel genes, such as Kir3.

Simulated Microgravity and Hypergravity Affect the Expression Level of Soluble Guanylate Cyclase, Adenylate Cyclase, and Phosphodiesterase Genesin Rat Ventricular Cardiomyocytes.

Ion channels activity is regulated through soluble guanylate cyclase (sGC) and adenylate cyclase (AC) pathways, while phosphodiesterases (PDE) control the intracellular levels of cAMP and cGMP. Here we applied RNA transcriptome sequencing to study changes in the gene expression of the sGC, AC, and PDE isoforms in isolated rat ventricular cardiomyocytes under conditions of microgravity and hypergravity. Our results demonstrate that microgravity reduces the expression of sGC isoform genes, while hypergravity increases their expression.

Simulated Microgravity Changes the Number of Mechanically Gated and Mechanosensitive Ion Channels Genes Transcripts in Rat Ventricular Cardiomyocytes.

The mechanoelectrical feedback in the heart is based on the work of mechanically gated (MGCs) and mechanosensitive (MSCs) channels. Since microgravity alters the heart's morphological and physiological properties, we hypothesized that the expression of both MGCs and MSCs would be affected. We employed RNA transcriptome sequencing to investigate changes in the gene transcript levels of MGCs and MSCs in isolated rat ventricular cardiomyocytes under control conditions and in a simulated microgravity environment.

Hypergravity Increases the Number of Gene Transcripts of Mechanically Gated and Mechanosensitive Ion Channels in Rat Ventricular Cardiomyocytes.

Since hypergravity changes the morphological and physiological properties of the heart, it was assumed that the expression of ion channels that respond to cell stretching or compressing, mechanically gated channels (MGC) and mechanosensitive channels (MSC), would be affected. Using RNA transcriptome sequencing, the change in the number of transcripts for MGC and MSC genes was studied in isolated rat ventricular cardiomyocytes under 4g hypergravity for 5 days. It was shown for the first time that hypergravity induces changes in the number of transcripts of MGC genes: an increase for TRPC1, TRPC3, TRPM7, TRPP1 (PKD1), TRPP2 (PKD2), TMEM63A, TMEM63B, but a decrease for TRPV2, Piezo1, Piezo2.

Identification of RNA reads encoding different channels in isolated rat ventricular myocytes and the effect of cell stretching on L-type Cacurrent.

Background: The study aimed to identify transcripts of specific ion channels in rat ventricular cardiomyocytes and determine their potential role in the regulation of ionic currents in response to mechanical stimulation. The gene expression levels of various ion channels in freshly isolated rat ventricular cardiomyocytes were investigated using the RNA-seq technique. We also measured changes in current through Ca1.

Protein Extract of a Probiotic Strain of and Bacterial ClpB Protein Improve Glucose Tolerance in Mice.

A commercial strain of () 4597 bacteria was shown to reduce food intake and promote weight loss, effects possibly induced by the bacterial protein ClpB, an antigen-mimetic of the anorexigenic α-melanocyte-stimulating hormone. A decrease in the basal plasma glucose levels was also observed in overweight fasted humans and mice receiving . However, it is not known whether influences sweet taste preference and whether its protein extract or ClpB are sufficient to increase glucose tolerance; these are the objectives tested in the present study.

Modulator chip based on semiconductor heterostructures with a surface diffraction grating for laser beam steering.

Design parameter optimization of a chip based on a heterostructure with a surface diffraction grating for laser beam angle modulation was carried out. It was found that the widest field of view is achieved at outcoupling angles close to the total internal reflection. The highest energy efficiency is provided by using epitaxy Bragg reflector on the substrate side.

Allelic variation of the Tas1r3 taste receptor gene affects sweet taste responsiveness and metabolism of glucose in F1 mouse hybrids.

In mammals, inter- and intraspecies differences in consumption of sweeteners largely depend on allelic variation of the Tas1r3 gene (locus Sac) encoding the T1R3 protein, a sweet taste receptor subunit. To assess the influence of Tas1r3 polymorphisms on feeding behavior and metabolism, we examined the phenotype of F1 male hybrids obtained from crosses between the following inbred mouse strains: females from 129SvPasCrl (129S2) bearing the recessive Tas1r3 allele and males from either C57BL/6J (B6), carrying the dominant allele, or the Tas1r3-gene knockout strain C57BL/6J-Tas1r3tm1Rfm (B6-Tas1r3-/-). The hybrids 129S2B6F1 and 129S2B6-Tas1r3-/-F1 had identical background genotypes and different sets of Tas1r3 alleles.

Ultrabroad tuning range (100 nm) of external-cavity continuous-wave high-power semiconductor lasers based on a single InGaAs quantum well.

An external cavity in Littrow configuration based on a reflective diffraction grating and a high-power semiconductor laser based on an asymmetric heterostructure with low optical loss was studied. A continuous-wave optical output power of 13 W with a linewidth of 0.15 nm was achieved for an external-cavity laser.

Effect of TRPV1 on Activity of Isoforms of Constitutive Nitric Oxide Synthase during Regulation of Bicarbonate Secretion in the Stomach.

Application of mild irritants (1 M NaCl; pH 2.0) on the gastric mucosa potentiates the protective secretion of bicarbonates by epithelial cells. This response is mainly mediated by capsaicin-sensitive afferent nerve endings located in the submucosa.

Interaction of Constitutive Nitric Oxide Synthases with Cyclooxygenases in Regulation of Bicarbonate Secretion in the Gastric Mucosa.

Neuronal NO synthase blocker 7-nitroindazole suppressed bicarbonate secretion in rat gastric mucosa induced by mild local irritation with 1 M NaCl (pH 2.0). Non-selective blocker of neuronal and endothelial synthases, Nω-nitro-L-arginine (L-NNA), did not affect HCO production, but inhibited secretion after pretreatment with omeprazole.

[EFFECT OF T1R3 RECEPTOR PROTEIN DELETION ON GLUCONEOGENESIS AND LIPID METABOLISM IN MICE].

Receptors of the T1R family are molecular sensors for sweet taste stimuli. They are expressed not only in the oral cavity, but in most of endocrine cells controlling homeostasis of glucose as well as in adipocytes. Earlier, we have demonstrated that deletion of the Taslr3 gene, which encodes the T1R3 protein, reduces glucose tolerance, elevates insulin resistance and cause a decrease of blood glucose level after food deprivation.

[ROLES OF CONSTITUTIVE SYNTHASES OF NITRIC OXIDE IN THE REGULATION OF GASTRIC BICARBONATE SECRETION INDUCED BY MILD IRRITATION OF THE MUCOSA].

Roles of isoforms of constitutive synthase of nitric oxide, neuronal or endothelial (nNOS or eNOS), in control of gastric bicarbonate secretion induced by mild irritation of the gastric mucosa was assessed at the normoacid state or after blockade of gastric acid secretion with omeprazole. In anesthetized rats, the concentration of HCO3- in luminal perfusate was calculated basing on measurements of pH/PCO2. Mucosal irritation during 20 min with acidic hypertonic solution (1 M NaCl, pH 2.

Impaired Glucose Metabolism in Mice Lacking the Tas1r3 Taste Receptor Gene.

The G-protein-coupled sweet taste receptor dimer T1R2/T1R3 is expressed in taste bud cells in the oral cavity. In recent years, its involvement in membrane glucose sensing was discovered in endocrine cells regulating glucose homeostasis. We investigated importance of extraorally expressed T1R3 taste receptor protein in age-dependent control of blood glucose homeostasis in vivo, using nonfasted mice with a targeted mutation of the Tas1r3 gene that encodes the T1R3 protein.

The Involvement of the T1R3 Receptor Protein in the Control of Glucose Metabolism in Mice at Different Levels of Glycemia.

The heterodimeric protein T1R2/T1R3 is a chemoreceptor mediating taste perception of sugars, several amino acids, and non-caloric sweeteners in humans and many other vertebrate species. The T1R2 and T1R3 proteins are expressed not only in the oral cavity, but also in the intestine, pancreas, liver, adipose tissue, and in structures of the central nervous system, which suggests their involvement in functions other than gustatory perception. In this study, we analyzed the role of the T1R3 protein in regulation of glucose metabolism in experiments with the gene-knockout mouse strain C57BL/6J- (), with a deletion of the gene encoding T1R3, and the control strain C57BL/6ByJ with the intact gene.

[Involvement of Tas1r3 receptor protein in control of the metabolism of glucose at different levels of glycemia in mice].

The heterodimeric protein T1R2/T1R3 is a chemoreceptor mediating taste perception of sugars, several amino acids, and non-caloric sweeteners in humans and many other vertebrate species. The T1R2 and T1R3 proteins are expressed not only in the oral cavity, but also in the intestine, pancreas, liver, adipose, tissue, and in structures of the central nervous system, which suggests their involvement in functions other than gustatory perception. In this study, we analyzed the role of the T1R3 protein in regulation of glucose metabolism in experiments with the gene-knockout mouse strain C57BL6J-Tas1r3(tm1Rfm) (Tas1r3-/-), with a deletion of the Tas1r3 gene encoding T1R3, and the control strain C57BL/6ByJ with the intact gene.

Dietary free amino acids and the gastric phase of digestion.

In the stomach, pre-absorptive perception of food constituents is of particular importance in maintaining secretion and motility that matches the quantity and quality of nutrients. Products of food protein hydrolysis, free amino acids and short peptides, are the most potent chemical stimulants of the gastric phase of digestion. They are recognized by a variety of extracellular receptors belonging to the G-protein-coupled receptor superfamily, which are expressed by gastric mucosal exocrine and endocrine cells.

Effect of proton pump inhibitors on the secretion of bicarbonates and pepsinogen induced by chemical stimulation of the gastric mucosa.

Proton pump inhibitors were shown to affect the sensitivity of the gastric mucosa to chemical agents. This effect is associated with inhibition of proton back-diffusion and increase in the permeability of the gastric epithelium. We studied the effect of omeprazole on gastric secretion of bicarbonates and pepsinogen induced by irritation of the gastric mucosa in narcotized rats with a hypertonic solution of high acidity (500 mM NaCl, pH 2.

[Effect of mild irritants on gastric outputs of bicarbonates and pepsinogen depends on the rate of acid secretion].

The aggressive luminal content in the stomach activates gastroprotective processes affecting exocrine and endocrine secretion of gastric glands and permeability of the pre-epithelial mucus layer. The aim of the study was to investigate effects of chemical irritants similar to physiological characteristics of digestion (pH 2.0 and/or 500 mM NaCl) on outputs of bicarbonates and pepsinogen as well as assess the role of endogenous acid production in control ofnon-parietal secretion during irritation of the gastric mucosa.

Genetics of sweet taste preferences.

Sweet taste is a powerful factor influencing food acceptance. There is considerable variation in sweet taste perception and preferences within and among species. Although learning and homeostatic mechanisms contribute to this variation in sweet taste, much of it is genetically determined.

Dietary glutamate signal evokes gastric juice excretion in dogs.

Background: Dietary-free L-glutamate (Glu) in the stomach interacts with specific Glu receptors (T1R1/T1R3 and mGluR1-8) expressed on surface epithelial and gastric gland cells. Furthermore, luminal Glu activates the vagal afferents in the stomach through the paracrine cascade including nitric oxide and serotonin (5-HT).

Aim: To elucidate the role of dietary Glu in neuroendocrine control of the gastrointestinal phase of gastric secretion.

Effect of free dietary glutamate on gastric secretion in dogs.

The amino acid, L-glutamate, which is abundant in many foodstuffs, is a potent stimulator of gastric vagal afferents. The aim of the study was to evaluate a role of dietary glutamate in neuroendocrine control of gastric secretion of acid, pepsinogen, and fluid. In mongrel dogs with small gastric pouches surgically prepared according to Pavlov (vagally innervated) or Heidenhain (vagally decentralized), secretion in a pouch was induced by infusion into the main stomach of an amino acid-rich diet lacking glutamate (Elental) or the same diet supplemented with monosodium glutamate (MSG).

Dietary monosodium glutamate enhances gastric secretion.

Dietary L-glutamate (Glu), an amino acid abundant in many foodstuffs in a free form, is able to modulate physiological functions in the stomach, including secretion and motility. Recently, specific receptors for Glu were identified in the apical membrane of chief cells in the lower region of fundic glands and in the somatostatin-secreting D-cell fraction of the gastric mucosa. This Glu-sensing system in the stomach is linked to activation of the vagal afferents.