Target-field specificity in the induction of retinal neurite outgrowth.

Nasal and temporal microexplants from the retina of the chicken embryo (E6; White Leghorn) were cultured on a collagen gel in the presence of extract from anterior or posterior E18 optic tectum. After 4 days of incubation maximum neurite lengths were measured as a function of protein concentration (1-500 micrograms/ml). Temporal retina was stimulated by both extracts but maximum neurite growth was obtained with anterior optic tectum at 500 micrograms/ml. Conversely, nasal retinal fiber outgrowth was best stimulated by posterior tectum, with maximum neuritic extension occurring at a concentration of 60 micrograms/ml. The stimulation was exerted by soluble protein fractions. The results show that topographically distinct axonal target fields of the optic tectum can selectively stimulate growth of neurites from the appropriate region of the retina.

Protein analysis of myelin isolated from the CNS of fish: developmental and species comparisons.

The protein composition of myelin isolated from the CNS of four different fish species (trout, goldfish), eel, Tilapia) was analysed by SDS-polyacrylamide gel electrophoresis and compared with that of pig and rat brain. Thereby the following features were found typical to the myelin of fish: (1) a basic protein of particular low molecular weight, (2) the entire absence of Wolfgram protein, (3) the appearance of an additional major component of medium molecular weight (around 36,000) and (4) a strong Con A-affinity exhibited by the intermediate proteins, being most clearly discernible in trout and eel myelin. During development of the trout brain, in particular, a myelin fraction could first be isolated from the brainstem at 14 days after hatching and the myelin yield steadily increased during the first year of life. In tectum and cerebellum main myelin accumulation was stated during the third and seventh month. Concomitantly marked changes in the relative distribution of major myelin proteins were observed: especially the IP1-protein showed a marked increase during the first half year, while the relative amount of the 36-K protein was gradually declining during the same time.

[Nuclear proteins and nucleic acids during differentiation of neurons in the spinal cord ganglia, spinal cord and tectum opticum in chickens. Cytophotometric study with computation programs]. / Iadernye belki i nukleinovye kisloty v protsesse differentsiatsii neironov spinnomozgovogo gangliia, spinnogo mozga i zritel'noi pokryshki (tectum opticum) kuritsy. Tsitofotometricheskoe issledovanie s programmami raschetov.

By means of doublewave cytophotometry of the histological sections and smears performed with the device mtsfv-1 (lomo) it has been demonstrated that differentiation of some neurons of the spinal ganglia and the spinal cord is accompanied with hyperreplication of DNA amount exceeding the diploid contents, while the large neurons in layer III of the tectum opticum remain diploid. In the process of differentiation an increased amount of RNA and histones, and decreasing portion of histones sented for the microcalculator b3-21.

Determination of choline and acetylcholine in distinct rat brain regions by stable isotope dilution and field desorption mass spectrometry.

The determination of choline and acetylcholine by field desorption mass spectrometry from rat brain tissue samples has been demonstrated. Essential points of the assay are the use of stable isotope labelled internal standards, a simple ion pair extraction procedure, direct analysis of the quaternary ammonium ions without derivatization, and accumulation of the electrically recorded field desorption ion signals with a multi-channel analyser. The analysis of sample amounts in the picogram range gave quantitative data of good precision (0.6--10% standard deviation).

[Effect of visual deprivation on the composition of structural proteins of the visual system of rabbit brain]. / Vliianie zritel'noi deprivatsii na sostav strukturnykh belkov zritel'noi sistemy mozgarolikov.

Composition of membrane proteins of the visual system structures of normal and dark-reared rabbits (for 2 1/2 months from birth) was studied by using polyacrylamide gel electrophoresis. Solubilization of membrane proteins was carried out using a 1% solution of Triton X-100 and a 0.1% solution of sodium dodecylsulfate, in succession. One fraction representing the fraction of high-molecular proteins was absent in membrane proteins of the visual analyser in the dark-reared animals; there was also a change in the percentage content of proteins in different fractions in comparison with the normal. The data obtained led to the conclusion that visual deprivation caused marked quantitative and qualitative reconstruction in the composition of membrane proteins of the brain with some specific characteristics for the formation of the visual analyser.

Peculiarities in the changes of catecholamine level in the brain, blood, and adrenals of dogs and rats in ontogenesis.

The norepinephrine content of the whole brainstem and of its different parts and the epinephrine and norepinephrine (NE) content in the blood and adrenals in dogs and rats during ontogenesis were studied. The catecholamine (CA) level in the blood and different parts of the dog brainstem increased to the age of 20-30 days and then decreased. The NE value of the whole dog brainstem increased to the age of 9-30 days, and then decreased. The content of NE of the rat brainstem increased to the age of 120 days and then decreased. The amount of CA of the dog and rat adrenals increased progressively from birth to adulthood. The CA brain and adrenal level of dogs during postnatal ontogenesis was lower than in rats.

[Histochemical investigations on sialic acid containing compounds in the CNS of teleosts (author's transl)]. / Histochemischer Nachweis Sialinsäure-haltiger Verbindungen im ZNS von Teleosteern

By means of histochemical experiments the qualitative (microphotographs) and quantitative (cytophotometry) distribution of sialic acid containing compounds was investigated in the mesencephalon and cerebellum of Carassius carassius. 1. The perikarya of nerve cells are especially stained by means of Azur A. 2. Nerve fibres, on the other hand, showed positive reactions with colloidal ironhydroxyd (CIH). 3. In different structures of the CNS the intensity of CIH-staining is decreased up to about 55% following treatment with neuraminidase. 4. There are no differences in the reactions of 7 degrees C as compared to 20 degrees C adapted animals.