Suppression of fatty acid β-oxidation and energy deficiency as a cause of inhibitory effect of E. coli lipopolysaccharide on osmotic water transport in the frog urinary bladder.

Previously we showed that arginine-vasotocin (AVT)-stimulated osmotic water permeability (OWP) of the frog urinary bladder was decreased if the mucosal side of the bladder has been naturally colonized by Gram-negative bacteria, or if bacterial lipopolysaccharide (LPS) was introduced into the lumen of the isolated bladder (J. Exp. Zool.

Mitochondrial-Targeted Antioxidant MitoQ Prevents Lipopolysaccharide-Induced Accumulation of Triacylglycerol and Lipid Droplets Biogenesis in Epithelial Cells.

The effect of bacterial lipopolysaccharide (LPS) on eukaryotic cell could be accompanied by a significant metabolic shift that includes accumulation of triacylglycerol (TAG) in lipid droplets (LD), ubiquitous organelles associated with fatty acid storage, energy regulation and demonstrated tight spatial and functional connections with mitochondria. The impairment of mitochondrial activity under pathological stimuli has been shown to provoke TAG storage and LD biogenesis. However the potential mechanisms that link mitochondrial disturbances and TAG accumulation are not completely understood.

Effects of ERK1/2 kinases inactivation on the nigrostriatal system of Krushinsky-Molodkina rats genetically prone to audiogenic seizures.

Unlabelled: Recently, we demonstrated that inhibition of ERK1/2 activity by SL-327 treatment blocks seizure behavior in Krushinsky-Molodkina (KM) rats, which was mediated by altering of GABA and glutamate release mechanism in the hippocampus. Basal ganglia representing various subcortical cell groups play a significant role in the regulation of motor activity, including epileptiform seizures.

Objectives:  To verify if nigrostriatal system could be also affected by SL-327 treatment we analyzed the expression of tyrosine hydroxylase, D1 and D2 dopamine receptors, NR2B subunit of NMDA receptor as well as vesicular glutamate transporter VGLUT2 and glutamic acid decarboxylases GAD65/67 in the striatum and substantia nigra of KM rats.

ATP-consuming processes in hepatocytes of river lamprey Lampetra fluviatilis on the course of prespawning starvation.

The work was performed to establish which of the major ATP-consuming processes is the most important for surviving of hepatocytes of female lampreys on the course of prespawning starvation. The requirements of protein synthesis and Na(+)-K(+)-ATPase for ATP in the cells were monitored by the changes in mitochondrial membrane potential (MMP) in the presence of corresponding inhibitors from the peak of metabolic depression (January-February) to the time of recovery from it (March-April) and spawning (May). Integrity of lamprey liver cells was estimated by catalytic activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in blood plasma.

Colonization of frog Rana temporaria L. urinary bladder by Gram-negative bacteria leads to decreased effect of arginine-vasotocin on water reabsorption from the urinary bladder.

In frogs and toads the urinary bladder is very important for the maintenance of water balance due to its ability to store water which can be reabsorbed under the action of arginine-vasotocin (AVT). The usage of isolated bladders as a model for studying the osmotic water permeability (OWP) regulation has a disadvantage which relates to high variability of AVT effect among individuals, some showing insensitivity to the hormone. We hypothesized that the response of the bladder to AVT could depend on the colonization of the mucosal epithelium by Gram-negative bacteria.

Frog urinary bladder epithelial cells express TLR4 and respond to bacterial LPS by increase of iNOS expression and L-arginine uptake.

As in mammals, epithelium of the amphibian urinary bladder forms a barrier to pathogen entry and is a first line of defense against penetrating microorganisms. We investigated the effect of Escherichia coli LPS on generation of nitric oxide (NO), a critically important mediator during infectious processes, by primary cultured frog (Rana temporaria) urinary bladder epithelial cells (FUBEC). It was found that FUBEC constitutively express Toll-like receptor 4 (TLR4), a receptor of LPS, and respond to LPS (10 μg/ml) by stimulation of inducible nitric oxide synthase (iNOS) mRNA/protein expression and NOS activity measured by nitrite produced in the culture medium and by citrulline assay.

Prostaglandin E2 inhibits vasotocin-induced osmotic water permeability in the frog urinary bladder by EP1-receptor-mediated activation of NO/cGMP pathway.

PGE(2) is a well-known inhibitor of the antidiuretic hormone-induced increase of osmotic water permeability (OWP) in different osmoregulatory epithelia; however, the mechanisms underlying this effect of PGE(2) are not completely understood. Here, we report that, in the frog Rana temporaria urinary bladder, EP(1)-receptor-mediated inhibition of arginine-vasotocin (AVT)-induced OWP by PGE(2) is attributed to increased generation of nitric oxide (NO) in epithelial cells. It was shown that the inhibitory effect of 17-phenyl-trinor-PGE(2) (17-ph-PGE(2)), an EP(1) agonist, on AVT-induced OWP was significantly reduced in the presence of 7-nitroindazole (7-NI), a neuronal NO synthase (nNOS) inhibitor.

Nitric oxide inhibits arginine-vasotocin-induced increase of water osmotic permeability in frog urinary bladder.

The present study addressed the question of whether nitric oxide (NO) participates in regulation of osmotic water permeability in the urinary bladder of the frog Rana temporaria L. Experiments were carried out on isolated, paired hemi-bladders filled with amphibian Ringer solution diluted 1:10 with distilled water. Sodium nitroprusside (SNP, 125-250 micro M), an NO donor, markedly attenuated the increase of osmotic water flow elicited by arginine-vasotocin (AVT) (AVT 10(-10) M: 2.

Regulation of urea permeability in frog urinary bladder by prostaglandin E(2).

The present study was performed to investigate the role of prostaglandin E(2) (PGE(2)) in the regulation of urea transport in the frog urinary bladder, which is known to occur via a specialized arginine-vasotocin- (AVT-) regulated urea transporter. The bladders isolated from Rana temporaria L. were filled with amphibian Ringer solution containing 370 Bq/ml (0.