It was thought previously that cardiac muscle gap junctions provide low-resistance connections between cells and permit the local-circuit current to flow. Some evidences show that myocardial cells may not require low-resistance connections for successful propagation of the action potential (AP). It seems that some other types of mechanisms must be involved in AP propagation. In this article, we...

Vertebrate gap junctions, composed of proteins from the connexin gene family, play critical roles in embryonic development, co-ordinated contraction of excitable cells, tissue homoeostasis, normal cell growth and differentiation. Phosphorylation of connexin43, the most abundant and ubiquitously expressed connexin, has been implicated in the regulation of gap junctional communication at several ...

A method is described that uses trypsin digestion combined with collagenase-hyaluronidase which produces a population of gap junction vesicles. The hexagonal lattice of subunits ("connexons") comprising the gapjunctions appears unaltered by various structural criteria and by buoyant density measurements. The gap junction vesciles are closed by either a single or a double profile of nonjunctiona...

Dynamic structuring and functions of perisynaptic astrocytic processes and of the gap junction network within a single astrocyte are outlined. Motile perisynaptic astrocytic processes are generating microdomains. By contacting and retracting of their endfeet an appropriate receptor pattern is selected that modulates the astrocytic receptor sheath for its activation by neurotransmitter substance...

Cortical oscillations are thought to be involved in many cognitive functions and processes. Several mechanisms have been proposed to regulate oscillations. One prominent but understudied mechanism is gap junction coupling. Gap junctions are ubiquitous in cortex between GABAergic interneurons. Moreover, recent experiments indicate their strength can be modified in an activity-dependent manner, s...

Gap junctions are cellular contact sites composed of clustered connexin transmembrane proteins that act in dual capacities as channels for direct intercellular exchange of small molecules and as structural adhesion complexes known as gap junction nexuses. Depending on the connexin isoform, the cluster of channels (the gap junction plaque) can be stably or fluidly arranged. Here we used confocal...

Brn4, which encodes a POU transcription factor, is the gene responsible for DFN3, an X chromosome-linked, non-syndromic type of hearing loss. Brn4-deficient mice have a low endocochlear potential (EP), hearing loss, and ultrastructural alterations in spiral ligament fibrocytes, however the molecular pathology through which Brn4 deficiency causes low EP is still unclear. Mutations in the Gjb2 an...

The fate of gap junctions in dissociated adult myocytes, maintained for up to 22 hours in culture medium, was investigated by semiquantitative analysis of thin sections and by freeze-fracture electron microscopy. Gap junctions in the dissociated myocyte are intact bimembranous structures seen either as invaginated surface-located structures or as annular profiles in the cytoplasm. Surface-locat...

The eye lens consists of layers of tightly packed fiber cells, forming a transparent and avascular organ that is important for focusing light onto the retina. A microcirculation system, facilitated by a network of gap junction channels composed of connexins 46 and 50 (Cx46 and Cx50), is hypothesized to maintain and nourish lens fiber cells. We measured lens impedance in mice lacking tropomoduli...

2-Aminoethoxydiphenyl borate (2-APB), an inositol 1,4,5-triphosphate receptor modulator, inhibits capacitive current transients measured in normal rat kidney and human embryonic kidney 293 cells, an indication of blocking gap junction channels between these cells. Here, we used the dual whole-cell patch-clamp method to study the actions of 2-APB on gap junction channels formed by selected conne...