Connexin26 is responsible for anionic molecule permeability in the cochlea for intercellular signalling and metabolic communications.
AuthorsZhao HB
JournalEur J Neurosci
PubMed ID15869481
'Abstract A gap junction is composed of two hemichannels and possesses a relatively large pore size ( approximately 10-15 A), allowing passage of ions and molecules up to 1 kDa. Here, we report that connexin hemichannels and gap junctions in the guinea pig cochlea had significant charge selectivity among permeating ... More
Patch-clamp recordings from white matter glia in thin longitudinal slices of adult rat spinal cord.
'We developed a technique of whole cell patch-clamp recordings from white matter oligodendrocytes and astrocytes in 200-250 microm-thick horizontal slices of adult (>2 months, 240-260 g) rat thoracic spinal cord. The viability of the white matter, sectioned in Na(+)-free, low Ca(2+) media, and the function of axons were preserved for ... More
Gap junctional communication in the early Xenopus embryo.
AuthorsLandesman Y, Goodenough DA, Paul DL
JournalJ Cell Biol
PubMed ID10953017
'In the Xenopus embryo, blastomeres are joined by gap junctions that allow the movement of small molecules between neighboring cells. Previous studies using Lucifer yellow (LY) have reported asymmetries in the patterns of junctional communication suggesting involvement in dorso-ventral patterning. To explore that relationship, we systematically compared the transfer of ... More
Extracellular diffusivity determines contribution of high-versus low-affinity receptors to neural signaling.
AuthorsSavtchenko LP, Rusakov DA
JournalNeuroimage
PubMed ID15734347
'Diffusion-weighted magnetic resonance imaging detects physiological changes in the human brain by highlighting alterations in local diffusivity. However, the causal link between brain tissue diffusivity and neural activity is poorly understood. Synaptic physiology studies in vitro coupled with biophysical modeling have suggested that extracellular diffusion affects the spatial profile of ... More
Properties of human connexin 31, which is implicated in hereditary dermatological disease and deafness.
AuthorsAbrams CK, Freidin MM, Verselis VK, Bargiello TA, Kelsell DP, Richard G, Bennett MV, Bukauskas FF
JournalProc Natl Acad Sci U S A
PubMed ID16549784
'The connexins are a family of at least 20 homologous proteins in humans that form aqueous channels connecting the interiors of coupled cells and mediating electrical and chemical communication. Mutations in the gene for human connexin 31 (hCx31) are associated with disorders of the skin and auditory system. Alterations in ... More
Preparation of Alexa Fluor 350-conjugated nonradioactive or 3H-labeled GM1 ganglioside derivatives with different ceramides.
AuthorsPanasiewicz M, Domek H, Fedoryszak N, Pacuszka T,
JournalAnal Biochem
PubMed ID18983810
Alexa Fluor 350 hydrazide (AF) was coupled to the aldehyde group at C-6 of terminal galactose of oxidized GM1 gangliosides containing different fatty acid residues (GM1s). The AF-GM1 hydrazones obtained were reduced with NaBH(4) or [3H]NaBH(4) and purified by high-performance thin layer chromatography (HPTLC) and high-performance liquid chromatography (HPLC). Final ... More
Hindered diffusion through an aqueous pore describes invariant dye selectivity of Cx43 junctions.
AuthorsHeyman NS, Burt JM,
JournalBiophys J
PubMed ID17921206
The permselectivity (permeance/conductance) of Cx43-comprised gap junctions is a variable parameter of junctional function. To ascertain whether this variability in junctional permselectivity is explained by heterogeneous charge or size selectivity of the comprising channels, the permeance of individual Cx43 gap junctions to combinations of two dyes differing in either size ... More
In vivo Stimulus-Induced Vasodilation Occurs without IP3 Receptor Activation and May Precede Astrocytic Calcium Increase.
AuthorsNizar K, Uhlirova H, Tian P, Saisan PA, Cheng Q, Reznichenko L, Weldy KL, Steed TC, Sridhar VB, Macdonald CL, Cui J, Gratiy SL, Sakadzic S, Boas DA, Beka TI, Einevoll GT, Chen J, Masliah E, Dale AM, Silva GA, Devor A,
JournalJ Neurosci
PubMed ID23658179
Calcium-dependent release of vasoactive gliotransmitters is widely assumed to trigger vasodilation associated with rapid increases in neuronal activity. Inconsistent with this hypothesis, intact stimulus-induced vasodilation was observed in inositol 1,4,5-triphosphate (IP3) type-2 receptor (R2) knock-out (KO) mice, in which the primary mechanism of astrocytic calcium increase-the release of calcium from ... More
The permeability of gap junction channels to probes of different size is dependent on connexin composition and permeant-pore affinities.
Gap junctions have traditionally been characterized as nonspecific pores between cells passing molecules up to 1 kDa in molecular mass. Nonetheless, it has become increasingly evident that different members of the connexin (Cx) family mediate quite distinct physiological processes and are often not interchangeable. Consistent with this observation, differences in ... More
A transient diffusion model yields unitary gap junctional permeabilities from images of cell-to-cell fluorescent dye transfer between Xenopus oocytes.
As ubiquitous conduits for intercellular transport and communication, gap junctional pores have been the subject of numerous investigations aimed at elucidating the molecular mechanisms underlying permeability and selectivity. Dye transfer studies provide a broadly useful means of detecting coupling and assessing these properties. However, given evidence for selective permeability of ... More
Mutation of a conserved threonine in the third transmembrane helix of alpha- and beta-connexins creates a dominant-negative closed gap junction channel.
AuthorsBeahm DL, Oshima A, Gaietta GM, Hand GM, Smock AE, Zucker SN, Toloue MM, Chandrasekhar A, Nicholson BJ, Sosinsky GE
JournalJ Biol Chem
PubMed ID16407179
Single site mutations in connexins have provided insights about the influence specific amino acids have on gap junction synthesis, assembly, trafficking, and functionality. We have discovered a single point mutation that eliminates functionality without interfering with gap junction formation. The mutation occurs at a threonine residue located near the cytoplasmic ... More