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Biomedical subjects

R W Burry

Publications and source records attributed to R W Burry.

42 records · Page 3Linked to original sources
PubMed1978

Electron microscopic autoradiography of the uptake of [3H]GABA in dispersed cell cultures of rat cerebellums. I. The morphology of the GABAergic synapse.

Dispersed cell cultures of rat cerebellums 21 days in vitro were incubated in saline containing 0.5 micrometer [3H]GABA for 5 min, fixed and prepared for electron microscopic autoradiography. Quantitative methods for analyzing the resulting autoradiographs were developed to distinguish lightly labeled neurons from heavily labeled (i.e. GABAergic) neurons. After a 3 week exposure, 2% of the presynaptic elements were found to be GABAergic. A longer incubation time of 15 min resulted in a greatly increased grain density over lightly labeled neurons, making it more difficult to distinguish them from the GABAergic neurons. When the concentration of [3H]GABA was increased to 1.0 micrometer, the grain densities over both GABAergic and other neurons increased to a similar extent. The morphology of the GABAergic synapses differed from that of the total population synapses. The GABAergic synapses had larger cross-sectional areas, lower densities of vesicles, greater numbers of vesicles, and thinner postsynaptic densities. Both the GABAergic and total population had similar lengths of the postsynaptic densities, cleft widths, vesicle sizes and types of postsynaptic elements. The morphology of the GABAergic synapse reported here is similar to that described for basket and stellate presynaptic elements in vivo.

Aminobutyrates↗
PubMed1978

A quantitative electron microscopic study of synapse formation in dispersed cell cultures of rat cerebellum stained either by Os-UL or by E-PTA.

Synapse formation was followed in dispersed cell cultures of rat cerebellums stained either by osmium-uranyl-lead (Os-UL) or by ethanolic phosphotungstic acid (E-PTA). The numerical densities of synapses stained by Os-UL were always significantly higher than those stained by E-PTA (from 3 to 35 days in vitro). This difference suggests that some portion of the populations of both immature and mature synapses was not stained by E-PTA. The width of the synaptic cleft (28.4nm) in synapses stained by E-PTA was only 9nm more than that of the cleft in synapses stained by Os-UL (19.4nm), suggesting that some portion of one or both of the synaptic membranes is stained by E-PTA. Analysis of data from 7 other staining procedures utilizing both ethanolic and aqueous solutions demonstrated that the differences in cleft width described above appear to be due to the various affinities of the stains for different portions of synaptic membranes, and do not represent differences due to shrinkage artifact. In examining the parameters of synaptic structure during development of the cultures, a statistically significant increase in both the height and width of the presynaptic dense projections was found. Changes in synaptic morphology during synaptogenesis in this culture system were similar to those reported for the cerebellar cortex in vivo.

Animals↗
PubMed1975

Coating sections for electron microscopic autoradiography: a stripping technique using liquid emulsion.

A coating technique for electron microscope autoradiography is described which combines the advantage of forming an emulsion film by a dipping method with the ease of coating sections already on grids. Sections are coated so that a formvar support film separates the section and the emulsion crystals. This intermediate layer of formvar ensures a random distribution of the emulsion crystals. Using light gold sections, Ilford L-4 emulsion and Microdol-X development, the resolution of this technique, as determined by the half distance method, was 150 nm. The additional layer of formvar slightly reduced the image quality with biological samples in the electron microscope. This technique has a minimal loss of resolution and image quality for moderate resolution electron microscope autoradiography.

Animals↗