The physiology of the kidney has long been understood, and its mechanisms are well described. The pathology of renal failure is also a deeply researched area. It seems logical, therefore, to create devices that can replace the lost normal function of the kidney.
View Article and Find Full Text PDFFront Endocrinol (Lausanne)
June 2023
The diluting and concentrating function of the kidney plays a crucial role in regulating the water homeostasis of the body. This function is regulated by the antidiuretic hormone, arginine vasopressin through the type 2 vasopressin receptor (V2R), allowing the body to adapt to periods of water load or water restriction. Loss-of-function mutations of the V2R cause X-linked nephrogenic diabetes insipidus (XNDI), which is characterized by polyuria, polydipsia, and hyposthenuria.
View Article and Find Full Text PDFThe antimicrobial effect of chitosan and synthetic chitosan derivatives has been confirmed on many Gram-positive and Gram-negative bacteria and fungi. The tests were carried out on pathogenic microorganisms, so the mechanism and concentration dependence of the inhibitory effect of chitosan were revealed. We conducted our tests on a probiotic strain, .
View Article and Find Full Text PDFMicroencapsulation and coating are preferred methods to increase the viability of the probiotic strains. The effect of microencapsulation technologies and materials used as microcapsule cores on viability is being investigated during development. In the present study, chitosan-coated and Eudragit L100-55-coated alginate microspheres were produced to encapsulate probiotic bacteria.
View Article and Find Full Text PDFThe urine concentrating function of the kidney is essential to maintain the water homeostasis of the human body. It is mainly regulated by the arginine-vasopressin (AVP), which targets the type 2 vasopressin receptor (V2R) in the kidney. The inability of V2R to respond to AVP stimulation leads to decreased urine concentration and congenital nephrogenic diabetes insipidus (NDI).
View Article and Find Full Text PDFNephrogenic syndrome of inappropriate antidiuresis (NSIAD) is a recently discovered rare disease caused by gain-of-function mutations of the V2 vasopressin receptor gene, AVPR2. To date, mutations of Phe229 and Arg137 have been identified as gain-of-function in the V2 vasopressin receptor (V2R). These receptor mutations lead to hyponatremia, which may lead to clinical symptoms in infants.
View Article and Find Full Text PDFBiased agonism on the type I angiotensin receptor (AT1-R) can achieve different outcomes via activation of G protein-dependent and -independent cellular responses. In this study, we investigated whether the biased activation of AT1-R can lead to different regulation and intracellular processing of the receptor. We analyzed β-arrestin binding, endocytosis, and subsequent trafficking steps, such as early and late phases of recycling of AT1-R in human embryonic kidney 293 cells expressing wild-type or biased mutant receptors in response to different ligands.
View Article and Find Full Text PDFG Protein Coupled Receptors (GPCR) can form dimers or higher ordered oligomers, the process of which can remarkably influence the physiological and pharmacological function of these receptors. Quantitative Bioluminescence Resonance Energy Transfer (qBRET) measurements are the gold standards to prove the direct physical interaction between the protomers of presumed GPCR dimers. For the correct interpretation of these experiments, the expression of the energy donor Renilla luciferase labeled receptor has to be maintained constant, which is hard to achieve in expression systems.
View Article and Find Full Text PDFLoss-of-function mutations of the type 2 vasopressin receptor (V2R) in kidney can lead to nephrogenic diabetes insipidus (NDI). We studied a previously described, but uncharacterized, mutation of the V2R (N321K missense mutation) of a patient with NDI. The properties of the mutant receptor were evaluated.
View Article and Find Full Text PDFInitiation and termination of signaling of the type I angiotensin receptor (AT(1)-R) can lead to dynamic changes in its localization in plasma membrane microdomains. Several markers were recently developed to investigate membrane microdomains. Here, we used several YFP-labeled fusion constructs (i.
View Article and Find Full Text PDFPrevious studies have demonstrated that molecules of the Ras signaling pathway are present in intracellular compartments, including early endosomes, the endoplasmic reticulum (ER), and the Golgi, and suggested that mitogens can regulate Ras activity in these endomembranes. In this study, we investigated the effect of angiotensin II (AngII) on intracellular Ras activity in living HEK293 cells expressing angiotensin type 1 receptors (AT(1)-Rs) using newly developed bioluminescence resonance energy transfer biosensors. To investigate the subcellular localization of AngII-induced Ras activation, we targeted our probes to various intracellular compartments, such as the trans-Golgi network (TGN), the ER, and early endosomes.
View Article and Find Full Text PDFWhole-body FDG PET examinations in 10 cases of epipharyngeal tumour (8 males, 2 females, mean age: 48 years) have been performed since January 1999. The PET examinations were aimed at the accurate staging, follow-up of the patients after the treatment, identification of recurrencies and localization of the unknown primary tumor. Functional imaging resulted in "upstaging" in 3 patients as compared to staging by the conventional diagnostic tools.
View Article and Find Full Text PDFNeurotoxicology
February 2001
The pH-dependent actions of aluminum(III) hydroxides (Al(III))on the voltage-activated sodium currents (VASCs) in the giant neurons of the pond snail Lymnaea stagnalis L. were studied by means of a conventional two-electrode voltage-clamp technique. The final concentration of Al(III) was 5-500 microM at pH 7.
View Article and Find Full Text PDFThe distribution and neuroanatomy of Mytilus inhibitory peptides (MIP)-containing neurons in the central nervous system and their innervation pattern in the peripheral nervous system of the pulmonate snail species, Lymnaea stagnalis and Helix pomatia, have been investigated immunocytochemically, by applying an antibody raised to GSPMFVamide. A significant number of immunoreactive neurons occurs in the central nervous system of both species (Lymnaea: ca 600-700, Helix: ca 400-500), but their distribution is different. In Lymnaea, labeled neurons are found in all central ganglia where a number of large and giant neurons, previously identified physiologically, reveal MIP immunoreactivity.
View Article and Find Full Text PDFActa Biol Hung
February 2001
Aluminum (Al) is one of the elements, which is frequently subjected to experiments, however, the neurological observations with it are rather conflicting. The cause of this controversiality is not known but relates to some human disorders such as Alzheimer's disease and others as well. We studied the time-dependent actions of AlCl3 base solutions on resting membrane potential (Em), input resistance (Rin) and spike shape in giant neurons of the snail Helix pomatia L.
View Article and Find Full Text PDFActa Biol Hung
February 2001
We showed how eugenol blocks the synaptic transmission and gave a possible interpretation how it inhibits the excitation-contraction coupling that several authors described previously. Eugenol acts both in the pre- and postsynaptic side of the neurons. It blocks the Ca2+-currents, decreases the membrane potential of the neurons, increases the inward resistance and decreases the GABA, ACh and glutamate evoked excitatory responses in submillimolar concentration.
View Article and Find Full Text PDFActa Biol Hung
February 2001
The possible role of serotonin and dopamine in the feeding of Helix pomatia was studied applying immunocytochemical, biochemical, and behavioral techniques as well as bioassay experiments. Immunocytochemistry showed that dopamine-containing (thyrosin-hydroxylase-immunoreactive) neuronal elements of the crop and the gizzard belong to the intrinsic part, whereas serotonin-containing (serotonin-immunoreactive) neuronal elements belong to the extrinsic part of the gastrointestinal nervous system. Bioassay studies on the spontaneous contractions of the crop and the gizzard showed that dopamine affected only the longitudinal muscle contractions by increasing both the tonus and contractility, whereas serotonin was effective on both the longitudinal and circular muscle contractions.
View Article and Find Full Text PDFThe distribution of serotonin-, tyrosine hydroxylase-, and FMRFamide-immunoreactive neuronal elements, as well as the concentrations of serotonin and dopamine in the different parts of the gastrointestinal tract, were studied in the snail Helix pomatia. The sensitivity of the spontaneous contractions of the alimentary tract to serotonin, dopamine, and FMRFamide was also tested. Serotonin-, tyrosine hydroxylase-, and FMRFamide-immunoreactive elements could be demonstrated in each part of the gastrointestinal tract, but they showed different innervation patterns.
View Article and Find Full Text PDFActa Biol Hung
December 1999
The actions of guaiacol (2-methoxy-phenol), vanillin (4-hydroxy-3-methoxy-benzaldehyd) and other vanilloid compounds such as zingerone (4-/4-hydroxy-3-methoxyphenyl/-2-butanon) and eugenol(2-methoxy4-/2-propenyl/phenol) were investigated on the fast outward potassium currents (A-type currents) in molluscan neurons. Guaiacol (0.01-0.
View Article and Find Full Text PDF1. The effects of aluminum on voltage activated sodium currents (VASCs) were investigated by using the conventional two-electrode voltage clamp technique in Lymnaea stagnalis L. neurons.
View Article and Find Full Text PDFActions of zinc, copper, lead and mercury ions on identified neurons and neuronal synapses of the snail, Helix pomatia L. were examined by use of electrophysiological methods. The studied metal ions depolarized the membrane and decreased the resistance but the neuronal excitability changed differentially.
View Article and Find Full Text PDFAluminum compounds (Al) increased the membrane potential (Em) and decreased the input resistance (Rin) of identified snail neurons. The neuronal excitability increased after Al withdrawal in the washing period. Cumulative Al applications caused dose-dependent modulation of Em and Rin in most of the studied neurons.
View Article and Find Full Text PDFMorphological changes induced by capsaicin were studied in the serotonergic metacerebral giant neurons of the cerebral ganglia of Helix pomatia under in vitro conditions. Capsaicin at a concentration of 10(-4)M caused characteristic structural alterations in the giant serotonergic neurons but did not significantly influence serotonin immunoreactivity in the neurons. At the light-microscopic level, the most conspiciuous structural alterations were swelling of the cell bodies, which contained a swollen pale nucleus.
View Article and Find Full Text PDFActa Biol Hung
February 1997
Modulatory actions of Zn2+ (0.05-2 mM) on spontaneous, stimulus evoked excitatory postsynaptic potentials (EPSPs) or currents (EPSCs) and GABA, L-glutamate induced depolarizations were examined in current- and voltage-clamp conditions. Identified and unidentified Helix pomatia L.
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