Distribution of H3-dimetacrine in rat cerebral cortex by electron microscopic autoradiography

Summary The cellular distribution of H³-dimetacrine in rat cerebral cortex was studied by electron microscopic autoradiography. A considerable proportion of autoradiographic grains (40.6%) was located over the synaptic areas, while the other structures (i.e., dendrites, axons, glial and neuronal cells) contained less autoradiographic activity.Acknowledgments. The authors wish to thank Siegfried AG., Switzerland, for the generous supply of 3-bromo-dimetacrine. Dimetacrine was kindly donated by Nippon Chemiphar Co., Ltd., Tokyo, Japan.     

Depression of neurones in the rat cerebral cortex by leptazol

Summary The convulsant drug leptazol was applied by microiontophoresis to 116 neurones in the cerebral cortex of rats. The firing of 101 cells was reduced. Only 6 cells were excited.     

Brain stem projections to the cerebral cortex in the rat

Summary By means of the HRP method it was shown that the entire cerebral cortex, but in greater proportion the frontal and posterior temporo-parietal regions, receive fibres from the dorsal and medial raphe nuclei and from the locus coeruleus. In contrast, the pars compacta substantiae nigrae and the tegmental area send projections to the motor and cingular areas respectively.     

Ultrastructural observation on the tips of growing vascular cords in the rat cerebral cortex

Summary The distal ends of the vascular cord in the cerebral cortex are investigated electron microscopically in rats at the 13th postnatal day. The tip of the vascular cord consists of central cuboidal cells (primitive endothelial cells) and surrounding flat cells (primitive pericytes), and has no lumen. The primitive endothelial cells (tip cells) possess several long tentacles which contain only fibrous structures and extend through the neuropile.This study was supported in part by a grant in aid for Scientific Research from the Ministry of Education of Japan (No. 448085).     

Brain stem projections to the cerebral cortex in the rat.

By means of the HRP method it was shown that the entire cerebral cortex, but in greater proportion the frontal and posterior temporo-parietal regions, receive fibres from the dorsal and medial raphe nuclei and from the locus coeruleus. In contrast, the pars compacta substantiae nigrae and the tegmental area send projections to the motor and cingular areas respectively.     

Adenylate cyclase in the developing rat cerebral cortex and olfactory bulb

Activities of adenylate cyclase, measured either in the absence or presence of sodium fluoride and Triton X-100, are determined in cerebral cortex and olfactory bulb homogenate of rats of 1 to 35 days of postnatal age. Differences in properties of the enzyme in the 2 structures are demonstrated.     

Adenylate cyclase in the developing rat cerebral cortex and olfactory bulb

Summary Activities of adenylate cyclase, measured either in the absence of sodium fluoride and Triton X-100, are determined in cerebral cortex and olfactory bulb homogenate of rats of 1 to 35 days of postnatal age. Differences in properties of the enzyme in the 2 structures are demonstrated.     

Purification of ribonuclease inhibitor from pig cerebral cortex

Zusammenfassung Der natürliche Ribonuclease-Hemmstoff aus Schweinsgrosshirnrindengewebe konnte mit DEAE-Cellulose-Chromatographie, Hydroxylapatit-Chromatographie und Sephadex G-100 Gel-Filtration ca. 6500fach gereinigt werden. Der gereinigte RNase-Hemmstoff zeigte eine Hauptbande (etwa 80–85% des Totaleiweisses) und einige kleinere Bande bei der Polyacrylamid-Gel-Electrophorese. Untersuchungen über die Natur dieses Hemmstoffs werden weitergeführt.     

Differential effects of the serotonin receptors on cultured rat cerebral cortical neurons

Effects of serotonin (5-HT) on cerebral cortical neurons were examined by patch clamp techniques. 5-HT produced a variety of responses such as outward (19/73 patches/neurons), slow inward (15/73 patches/neurons), fast inward (8/73 patches/neurons), and mixed currents (initially fast inward deflection followed by an outward response: 2/73 patches/neurons), with a latency of 12 sec, 15 sec, 0 sec, and 0 sec respectively, at a holding potential of −60 mV in whole-cell patches. The fast inward currents were again evoked by a selective 5-HT3 receptor agonist, 1-(m-chlorophenyl)-biguanide hydrochloride (CPBG). In the cell-attached patch clamp configuration, 5-HT inside the patch pipette elicited single channel currents with slope conductances of 42 pS and 132 pS (4/42 patches/neurons). CPBG inside the patch pipette evoked inward single channel currents with a lower slope conductance of 41 pS (3/23 patches/neurons). In contrast, application of 5-HT or a 5-HT₂ receptor agonist, α-methyl-5-hydroxytryptamine-maleate, outside the patch pipette induced outward single channel currents with a major slope conductance of 140 pS (8/30 patches/neurons) or 135 pS (6/20 patches/neurons), respectively. These results indicate that the outward and fast inward currents may be mediated respectively by the 5-HT₂ receptor, which is coupled to a G-protein, and by the 5-HT₃ receptor, which contains the non-selective cation channel, and that the mixed type may be caused by both the 5-HT₂ and 5-HT₃ receptors. Received 27 September 1996; received after revision 4 November 1996; accepted 7 November 1996     

Steady potential responses from the rat cortex during conditioning

Zusammenfassung Während Versuchsreihen an Ratten über Gewöhnung, Paarung und Auslöschung wurden jeweils signifikante Veränderungen des kortikalen Bestandespotentials (Gleichspannung) als Antwort auf Schallreiz gemessen.

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Supported by a grant from the Medical Research Foundation of Texas.     

Investigations into the effects of ACTH on the half-life of mitochondrial proteins in the rat adrenal cortex

Summary ACTH elongates the half-life of the mitochondrial proteins from the rat adrenal cortex, and chloramphenicol inhibits this effect of ACTH. The hypothesis is advanced that the ACTH-provoked stabilization of the adrenocortical mitochondrial proteins requires continuous mitochondrial DNA-dependent protein synthesis.     

Possible regulation of membrane-associated cyclic AMP phosphodiesterase in rat cerebral cortex by lipids

Summary Cyclic AMP phosphodiesterase (PDE) in membrane fraction from rat cerebral cortex was activated by Triton X-100, and treatment at alkaline pH and with phospholipase C. These results suggest that membrane PDE exists in a latent form and is influenced by microenvironmental changes within the membrane. Furthermore, the PDE, unlike soluble enzyme, is not influenced by a protein activator and Ca⁺⁺.     

Cajal cells of the rabbit cerebral cortex

Resumen Las células deCajal en los animales estudiados, no poseen axon. Morfológicamente son similares a las grandes amacrinas de la plexiforme interna de la retina.

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Supported by a grant from The Seguridad Social, Instituto Nacional de Previsión.     

Effects of hyperphenylalaninaemia on the cerebral cortex at ultracellular levels

Resumen La alteración de la síntesis protéica en el SNC originada por los niveles altos de fenilalanina en sangre se refleja en una disminución de imágenes ribosomales en el citoplasma neuronal.     

Investigations into the effects of ACTH on the half-life of mitochondrial proteins in the rat adrenal cortex.

ACTH elongates the half-life of the mitochondrial proteins from the rat adrenal cortex, and chloramphenicol inhibits this effect of ACTH. The hypothesis is advanced that the ACTH-provoked stabilization of the adrenocortical mitochondrial proteins requires continuous mitochondrial DNA-dependent protein synthesis.     

The dopaminergic innervation as observed by immunohistochemistry using anti-dopamine serum in the rat cerebral cortex

By using an antiserum raised against dopamine bound to bovine serum albumin, thinner dopamine-labeled nerve terminals were visualized immunohistochemically within neocortical areas, in addition to well-documented dopaminergic innervation into the prefrontal and limbic cortices.