PubMed Health⌕ Search

Biomedical subjects

R Bing

Publications and source records attributed to R Bing.

10 recordsLinked to original sources
PubMed2000

Alpha 1E subunit of the R-type calcium channel is associated with myelinogenesis.

During myelinogenesis, we found an exceedingly strong, transient expression of the alpha(1E) gene for the R-type voltage-gated calcium channel in CNS white matter. This immunoreactivity appeared in glial cells along specific pathways of the brainstem, cerebellum, and telencephalon. The reactivity followed a wave that progressed from the brainstem at P5, to the cerebellar peduncles by P8, the arbor vitae by P14, and the granular layer by P17. The reactivity-peaked about 3-4 days later and decreased gradually to become negligible in all areas before adulthood. Ultrastructural analysis confirmed that alpha(1E) immunoreactivity was located in oligodendroglial somata, their projections, paranodal wraps and loose myelin sheaths. There was a distinct association of the channel protein reactivity on oligodendroglial membranes in contact with the axon. We propose that glial projections, contacting axons, sense axonal firing through small K(+) currents and open the high voltage R-type calcium channels to signal myelination.

Aging↗
PubMed1997

A single dose of kainic acid elevates the levels of enkephalins and activator protein-1 transcription factors in the hippocampus for up to 1 year.

Neuronal plasticity plays a very important role in brain adaptations to environmental stimuli, disease, and aging processes. The kainic acid model of temporal lobe epilepsy was used to study the long-term anatomical and biochemical changes in the hippocampus after seizures. Using Northern blot analysis, immunocytochemistry, and Western blot analysis, we have found a long-term elevation of the proconvulsive opioid peptide, enkephalin, in the rat hippocampus. We have also demonstrated that an activator protein-1 transcription factor, the 35-kDa fos-related antigen, can be induced and elevated for at least 1 year after kainate treatment. This study demonstrated that a single systemic injection of kainate produces almost permanent increases in the enkephalin and an activator protein-1 transcription factor, the 35-kDa fos-related antigen, in the rat hippocampus, and it is likely that these two events are closely associated with the molecular mechanisms of induction of long-lasting enhanced seizure susceptibility in the kainate-induced seizure model. The long-term expression of the proenkephalin mRNA and its peptides in the kainate-treated rat hippocampus also suggests an important role in the recurrent seizures of temporal lobe epilepsy.

Animals↗
PubMed1997

Plasmalemmal ATPase calcium pump localizes to inner and outer hair bundles.

Recent studies demonstrate calcium ion influx at the tips of hair cell stereocilia during mechano-transduction. These ions must be either pumped from the cytosol into the extracellular space or endoplasmic envelope, or else sequestered by binding to specific proteins. A plasma membrane calcium pump (ATPase-type) was analysed in whole-mounts of rat organ of Corti using a monoclonal antibody to a large cytoplasmic loop of this protein. The reactivity was particularly high on the tips of longer stereocilia and was found along the shafts. Inner hair cell stereocilia had much less reactivity than outer hair cells. The reactivity lined the plasma membrane of inner hair cell bodies while a higher reactivity appeared in the cytoplasm of outer hair cells. Supporting cells were unreactive. Ultrastructural examination confirmed the plasma membrane calcium pump location on stereocilia and along the endolymph surface of receptor cells. Reaction product lined the plasma membrane of stereocilia as intense puncta. More reactive puncta occurred near the distal ends of stereocilia and the number decreased toward the ciliary base. The endolymph plasma membrane over the cuticular notch was especially reactive. The finding of more intense pump reactivity at the tips of stereocilia than the base is consistent with the hypothesis that during transduction, calcium ions enter stereocilia, distally, and the ATPase plasma membrane calcium pump rapidly extrudes these ions to the extracellular space.

Adenosine Triphosphatases↗
PubMed1997

Long-term expression of Fos-related antigen and transient expression of delta FosB associated with seizures in the rat hippocampus and striatum.

Systemic administration of kainic acid (KA), an analogue of glutamic acid, causes limbic seizures and pathophysiological changes in adult rats that are very similar to human temporal lobe epilepsy. One of the earliest changes in gene expression after treatment with KA is the induction of immediate-early genes. The fos and jun families are frequently studied immediate-early genes that are induced by KA. Several groups, including ours, have recently reported that a 35-kDa Fos-related antigen (FRA) is induced for a protracted time by various stimuli. It has been suggested that this FRA is delta FosB, which has a molecular mass of approximately 35 kDa. The present study characterizes the long-term expression of FRA and delta FosB after systemic treatment with KA. Immunocytochemistry and western blot analysis using an antibody that cross-reacts with all known FRAs showed that a 35-kDa FRA was induced at high levels in both the hippocampus and striatum for up to 1 month by KA. A semiquantitative PCR analysis showed that delta FosB was induced by KA, but its expression lasted for only 6 h. This result was also verified by northern blot analysis. These results suggested that the 35-kDa FRA with long-term elevated levels seen with western blot analysis and immunocytochemistry is a new species of the FRA and not delta FosB. The long-term expression of FRA in both the hippocampus and striatum may be associated with the pathophysiological changes after KA administration.

Animals↗
PubMed1996

Immunohistochemical localization of Lyn (p56) protein in the adult rat brain.

Expression of a sarcoma proto-oncogene, c-lyn, was mapped in the adult rat brain using immunohistochemistry. Lyn protein was prevalent in restricted cell populations of the olfactory bulb and the basal forebrain which included nuclei of accumbens, fundal striatum, bed stria, ventral pallidum and central amygdala as well as deep entorhinal and pyriform cortices. Tightly packed Lyn-positive cells formed discrete multiple stripes crossing perpendicular to the rostral limb of the anterior commissure, and intense masses surrounding the caudal limb. In the thalamus, the habenula, anterodorsal nucleus and medial geniculate body, together with the paraventricular hypothalamic nuclei, had prominent reactive neuronal somata and dendrites in the neuropil. The lateral septal nucleus also had intense Lyn-positive neurons with overlapping dendritic fields. In addition, scattered neurons were evenly distributed throughout the striatum. The red, interpeduncular, auditory and trigeminal tract nuclei were intensely reactive. The cerebellar molecular layer was uniformly labeled except for a few isolated fiber bundles in the lowest part of this layer. The granule cells adjacent to the Purkinje cell layer appeared in reactive patches. In the spinal cord, the posteromarginal nucleus had intense labeling. The significance of this highly localized distribution pattern of Lyn protein may be related to connections forming functional compartments serving signal transduction within specific central nervous system circuitry.

Animals↗
PubMed1996

Ultrastructural localization of the plasmalemmal calcium pump in cerebellar neurons.

In a previous study, fluorescence labeling of a plasmalemmal ATPase protein with the 5F10 monoclonal antibody revealed prominent antigen in the cerebellar molecular layer surrounding the somata and dendrites of Purkinje cells. In the present study, this antibody labeled with silver enhanced nano-sized gold particles on semithin plastic sections revealed a clearly demarcated plasma membrane outlining the somata and entire dendritic arbors of Purkinje cells including their spines. Ultrastructural analysis of horseradish peroxidase preparations showed reaction product along the plasmalemma and extending on to the sub-plasmalemmal endoplasmic reticulum. In the granular layer, somata of granule cells were reactive, as were their dendritic extensions into glomeruli where reactive claws surrounded voids formed by mossy fiber rosettes. Somata and dendrites of cerebellar nuclear cells also had reactive zones that were limited to the plasma membrane and a narrow zone of the sub-plasmalemmal endoplasmic reticulum. Comparative labeling of this protein and P channel protein revealed similar plasmalemmal locations. This study shows that a specific calcium ATPase pump protein is located on the plasmalemma of certain types of cerebellar neurons. The ultrastructural distribution of calcium pump and P channel antibodies occurred in punctate sites along the plasma membrane of dendrites and spines of Purkinje cells. The close association between P-type calcium channels and the plasma membrane calcium pump is consistent with rapid extrusion of intracellular calcium from neurons endowed with large numbers of voltage-gated calcium channels.

Animals↗