Volume-regulated anion channels (VRACs) play an important role in controlling cell volume by opening upon swelling. Recent work has shown that heteromers of LRRC8A with other LRRC8 members (B, C, D, and E) form the VRAC. Here, we used Xenopus oocytes as a simple system to study proteins. We discovered adding fluorescent proteins C-terminus resulted constitutive channel activity. Using these constructs, reproduced previous findings indicating mediate osmolyte flux subunit-dependent kinetics...

Voltage-dependent K+ channels (VDPC) are expressed in most mammalian cells and involved the proliferation activation of lymphocytes. However, role VDPC macrophage responses is not well established. This study was undertaken to characterize macrophages determine their physiological during activation. Macrophages proliferate until an endotoxic shock halts cell growth they become activated. By inducing a schedule that similar pattern, we have identified non-transformed bone marrow-derived...

Voltage-dependent K(+) (Kv) currents in macrophages are mainly mediated by Kv1.3, but biophysical properties indicate that the channel composition could be different from of T-lymphocytes. mouse bone marrow-derived and Raw-264.7 sensitive to Kv1.3 blockers, unlike T-cells, express Kv1.5. Because Shaker subunits (Kv1) may form heterotetrameric complexes, we investigated whether Kv1.5 has a function Kv macrophages. co-localize at membrane, half-activation voltages pharmacology accounted for...

The regulation of neostriatal cholinergic function by tachykinins (TKs) has been studied measuring endogenous ACh released from rat slices. Septide (SEP; a highly selective substance P analog), neurokinin A (NKA), and B (NKB) elicited release in concentration-dependent manner. rank order potency was the following: NKB (EC50 approximately 0.5 nM) greater than NKA 7 SEP 12 nM). Spantide (SPA) less effective (39% inhibition) [D-Arg6, D-Trp7,9, N-Methyl-Phe8]-substance fragment 6-11 (53% at...

Neurotransmitters are stored in synaptic vesicles, where they have been assumed to be free solution. Here we report that Torpedo only 5% of the total acetylcholine (ACh) or ATP content is free, and rest adsorbed an intravesicular proteoglycan matrix. This matrix, which controls ACh release by ion-exchange mechanism, behaves like a smart gel. That is, it releases neurotransmitter changes its volume when challenged with small ionic concentration change. Immunodetection analysis revealed...

Kv1.3 activity is determined by raft association. In addition to Kv1.3, leukocytes also express Kv1.5, and both channels control physiological responses. Because the oligomeric composition may modify channel targeting membrane, we investigated heterotetrameric Kv1.3/Kv1.5 traffic in HEK cells. Kv1.5 generate multiple heterotetramers with differential surface expression according subunit composition. FRET analysis pharmacology confirm presence of functional hybrid channels. Raft association...

Trabecular meshwork (TM) cell shape, volume, contractility and their interactions with extracellular matrix determine outflow facility. Because volume seems essential to TM function, this study was conducted investigate further the ionic channels receptors involved in regulatory decrease roles modulating facility.Primary cultures of bovine cells were used. K(+) Cl(-) currents studied whole-cell patch clamping. Swelling induced by hypotonic shock. [Ca(2+)](i) measured loaded fura-2. Bovine...

1. The effects of adenosine (50 microM) and 2‐chloroadenosine (1‐25 were studied on Ca2+ currents in frog motor nerve endings. 2. associated with the synchronous, neurally evoked release acetylcholine (ACh) measured using either perineural or patch recording methods. Tetraethylammonium and/or 3,4‐diaminopyridine employed to block K+ currents. 3. depressed by omega‐conotoxin (1.5‐2.5 microM), Cd2+ (100 microM‐2 mM), Co2+ (500 microM‐5 mM) a reduction extracellular calcium concentration. Such...

Epsilon toxin (Etx) from Clostridium perfringens is a pore-forming protein that crosses the blood-brain barrier, binds to myelin, and, hence, has been suggested be putative agent for onset of multiple sclerosis, demyelinating neuroinflammatory disease. Recently, myelin and lymphocyte (MAL) identified key in cytotoxic effect Etx; however, association Etx with immune system remains central question. Here, we show selectively recognizes kills only human cell lines expressing MAL through direct...

The presence of ATP within cells is well established. However, also operates as an intercellular signal via specific purinoceptors. Furthermore, nonsecretory can release under certain experimental conditions. To measure and membrane currents from a single cell simultaneously, we usedXenopus oocytes. We simultaneously recorded luminescence. Here, show that be triggered in Xenopus oocytes by hyperpolarizing pulses. (3.2 ± 0.3 pmol/oocyte) generated slow inward current (2.3 0.1 μA). During...

Abstract Voltage-dependent potassium channels (Kv) in leukocytes are involved the immune response. In bone marrow-derived macrophages (BMDM), proliferation and activation induce delayed rectifier K+ currents, generated by Kv1.3, via transcriptional, translational, posttranslational controls. Furthermore, modulatory Kvβ subunits coassociate with Kvα subunits, increasing channel diversity function. this study we have identified mouse BMDM, studied their regulation during activation, analyzed...

1. Various types of anticholinesterasic agents have been used to improve the daily activities Alzheimer's disease patients. It was recently demonstrated that Galantamine, described as a molecule with properties, is also an allosteric enhancer human alpha4beta2 neuronal nicotinic receptor activity. We explored its effect on alpha7 acetylcholine (nAChR) expressed in Xenopus oocytes. 2. at concentration 0.1 microM, increased amplitude (ACh)-induced ion currents nAChR oocytes, but caused...

Abstract ATP is an electrically charged molecule that functions both in the supply of energy necessary for cellular activity and as intercellular signaling molecule. Although controlled secretion occurs via exocytosis granules vesicles, some cells, under certain conditions, other mechanisms control release. Gap junctions, channels formed by connexins link cytoplasm two adjacent passage ions molecules up to 1 kDa. The channel moieties called hemichannels, or connexons, it has been suggested...

Extracellular purines elicit strong signals in the nervous system. Adenosine-5'-triphosphate (ATP) does not spontaneously cross plasma membrane, and cells secrete ATP by exocytosis or through membrane proteins such as connexin hemichannels. Using a combination of imaging, luminescence electrophysiological techniques, we explored possibility that Connexin 32 (Cx32), expressed Schwann (SCs) myelinating peripheral system could be an important source nerves. We triggered release vivo from mice...

Abstract The epsilon toxin (Etx) from Clostridium perfringens has been identified as a potential trigger of multiple sclerosis, functioning pore‐forming that selectively targets cells expressing the plasma membrane (PM) myelin and lymphocyte protein (MAL). Previously, we observed Etx induces release intracellular ATP in sensitive cell lines. Here, aimed to re‐examine mechanism action investigate connection between pore formation release. We examined impact on Xenopus laevis oocytes human...

Over 1,500 cystic fibrosis transmembrane conductance regulator (CFTR) gene sequence variations have been identified in patients with (CF) and related disorders involving an impaired function of the CFTR chloride channel. However, detailed structure–function analyses only established for a few them. This study aimed evaluating impact eight N-terminus natural missense changes on channel behavior. By site-directed mutagenesis, we generated four variants N-terminal cytoplasmic tail (p.P5L,...

Extracellular ATP and its hydrolysis product adenosine modulate various reproductive functions such as those requiring contraction, hormone synthesis maintenance of fluid composition. Moreover, is a key molecule for sperm capacitation. nucleotide nucleoside levels are affected by cell surface ectonucleotidases, amongst which the ectonucleoside triphosphate diphosphohydrolase (E-NTPDase) family most abundant effective to hydrolyse ADP AMP. In female tract three members this have been recently...

Graphical Abstract figure legend HCN channels play an evolutionarily conserved pacemaker role in renal pelvic smooth muscle (RPSM) of lower and higher order mammals. The function hyperpolarization-activated cation (HCN) pacemakers remains controversial. Renal trigger contractions that expel waste from the kidney, have been localized to these tissues. To date, however, mechanisms underlying RPSM activity remain elusive. was investigated both (top left) (bottom mammalian models, which exhibit...