What Are Gap Junctions?

Gap connection can also be called connection or macular communication . (Although most neural tissues do not have gap junctions, they can also be called electrical synapses when found in neurons or nerves, such as nerve cells in the pulp.) Although ephapse has some similarities to gap junctions , But by modern definition, the two are different.

Gap junction

In vertebrates, gap junction hemichannels are mainly

1. DNA is converted into connexin RNA.

2. One connexin has four transmembrane

   1. Direct electrical communication between cells is allowed, although different connexin subunits can confer different single-channel conductances from about 30 pS to 500 pS.

   2. Allows chemical communication between cells by transmitting small

      Gap junctions have been observed in various animal organs and tissues where the cells are in contact with each other. From the 1950s to the 1970s, they were found in crawfish nerves, rat pancreas, liver, adrenal cortex, epididymis, duodenum, muscles,

      You can see that gap junctions work at the simplest level, as a direct cell-to-cell pathway for electrical currents, small molecules, and ions. Control of this communication allows complex downstream effects on multicellular organisms, as described below.

      Gap junction embryo, organ and tissue development

      In the 1980s, the more subtle but equally important role of gap connection communication has been studied. It was found that gap junction communication can be disrupted by the addition of anti-connexin antibodies to embryonic cells. Embryos with occluded gap junction regions fail to develop normally. The mechanism by which antibodies block gap junctions is unclear, but systematic studies have been performed to elucidate its mechanism. The refinement of these studies suggests that gap junctions seem to be key to the development of cell polarity and the animals are left / right symmetrical / asymmetric. Although the signals that determine the location of body organs appear to be dependent on gap junctions, so is the basic differentiation of cells in the later stages of embryonic development. Gap junctions have also been found to be responsible for the signaling that affects drugs. Conversely, some drugs have been shown to block gap junction channels.

      Gap connection gap junction and "bystander effect"

      Cell death

      The connotation of the "bystander effect" and its killing of innocent bystanders is also mediated by gap connections. When a cell is damaged due to a disease or injury and begins to die, the message is passed through a gap junction to an adjacent cell connected to the dying cell. This could cause other unaffected healthy bystander cells to die as well. Therefore, it is important to consider bystander effects in diseased cells, which opens the way for more funding and research to flourish. Later, bystander effects were also investigated for cells that were damaged by radiation or mechanical damage and thus wound healing. The disease also appears to affect the ability of gap junctions to play a role in wound healing.

      Although there is a tendency to focus on bystander effects in the disease due to the possibility of treatment pathways, there is evidence that a more important role exists in the normal development of tissues. The death of some cells and their surrounding matrix may be necessary for the tissue to reach its final configuration, and gap junctions are also essential for this process. There are more complex studies that attempt to combine our understanding of the simultaneous role of gap junctions in wound healing and tissue development.

      Gap connection electrical coupling area

      Gap junctions connect cells to the body of most animals electrically and chemically. Electrical coupling can work relatively quickly. The tissue in this section has a well-known function, observed to be coordinated by gap junctions, where intercellular signals occur in microseconds or less time frames.

      heart

      Gap junctions are particularly important in the myocardium: contraction signals effectively pass through gap junctions, causing myocardial cells to contract uniformly. With the exception of fully developed skeletal muscles and mobile cell types (such as sperm or red blood cells) in adults, gap junctions are expressed in almost all tissues of the body. Several human genetic diseases are associated with mutations in gap junction genes. Many of these affect the skin because this tissue relies heavily on gap junction communication to regulate differentiation and proliferation. Cardiac space junctions can be opened pharmacologically with rotigaptide.

      Neurons

      Gap connections located in neurons are often called electrical synapses. Before describing the gap junction structure, electrical measurements were used to discover electrical synapses. Electrical synapses are present throughout the central nervous system and have been found in the neocortex, hippocampus, vestibular nucleus, thalamic reticular nucleus, blue plaque, lower olive nucleus, trigeminal nucleus, ventral tegmental area, olfactory bulb, retina And vertebrate spinal cord.

      Observation of some weak neurons in the cerebellar glial cells coupled between blue spots and glial cells and Bergmann glial cells. It appears that astrocytes are coupled to other astrocytes and oligodendrocytes via gap junctions. In addition, mutations in the gap junction genes Cx43 and Cx56.6 lead to white matter degeneration similar to those observed in Pelizaeus-Merzbacher disease and multiple sclerosis.

      Connexins expressed at the junction of neuronal gaps include:

      1. m CX36

      2. mCX57

      3. m CX45

      MRNA was used to detect at least five other connexins (m Cx26, m Cx30.2, m Cx32, m Cx43, m Cx47) but there was no immunocytochemical evidence of corresponding proteins in the gap junctions defined by ultrastructure. Those mRNAs appear to be down-regulated or disrupted by cell type and cell lineage-specific microinterfering RNAs (miRNAs).

      Retina

      Neurons in the retina show extensive coupling within a population of one cell type and between different cell types.