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At least 19 recordsLinked to original sources
PubMed1976

[Activity of neurons of the hypothalamic suprachiasmatic nuclei and circadian rhythms: the role of the suprachiasmatic nuclei in rhythmic activities of neurons in the lateral hypothalamic area and ventromedian nuclei and the control of the pineal gland].

Unit activity of lateral hypothalamic area (LHA) and ventromedian nuclei (VMN) was recorded in urethane anesthetized male rats. A 5 to 10 sec, a 3 to 5 min and a circadian rhythmicity were observed. In about 15% of all neurons, spontaneous activity of LHA and VMN showed reciprocal relationships. Subthreshold stimuli applied at a slow rate in the septum and the suprachiasmatic nuclei (SCN) suppressed the rhythms without changing firing rates. On the other hand stimulation of the optic nerve at a rate of 5 to 10/sec increased firing rates in one third of neurons of SCN. Iontophoretically applied acetycholine increased 80% of tested neurons of SCN, whereas norepinephrine, dopamine and 5HT inhibited 64%, 60% and 75% of SCN neurons, respectively. These inhibitions were much stronger in neurons, the activity of which was increased by optic nerve stimulation. Stimulation of the SCN inhibited the tonic activity in cervical sympathetic nerves. These data suggest that SCN plays a significant role in controlling the rhythmic activity of LHA, VMN and the pineal gland. Dopamine and 5HT may be involved in regulation of the firings of SCN neurons.

Acetylcholine↗
PubMed1975

Microphotometry of rat liver nucleoproteins during the cell cycle, and comparison of diploid nuclei in the G2 period with tetraploid nuclei.

The following facts were established with a microphotometric investigation of isolated nuclei from rat liver in different stages of the cell cycle. During the mitotic wave occurring in the liver of newborn animals after injection of casein it was found that the naphtol yellow S (NYS) protein content of the nuclei increases about 30% during the G1-period. A second increase of around 70% was established during the S-phase whereas no increase could be observed during the G2-phase. An indication for the existence of a "critical protein mass" of the nuclei before the onset of the S-phase could be observed. The protein content of diploid nuclei in the G1-phase of adult animals is about 50% higher than in newborns. This makes it probable that there is no significant difference in the NYS-protein content of diploid nuclei in the G2-period and tetraploid nuclei of adult rats. No differences were observed between diploid nuclei in the G2-period of newborn rats and tetraploid nuclei of adult rats in their Fastgreen histon, RNA and SH plus SS content. The only criterion to distinguish between G2 nuclei and tetraploid nuclei seems to be the number of nucleoli, but this is rather unreliable.

Aging↗
PubMed1979

Cross-linking of proteins in nuclei and DNA-depleted nuclei from Friend erythroleukemia cells.

Reversible cross-linking of proteins in nuclei and DNA-depleted nuclei from Friend erythroleukemia cells was used as a probe to determine whether the protein structure was preserved following treatment with DNAase I. Interactions between histones were analyzed through cross-linking with 2-iminothiolane or dimethyl 3,3'-dithiobispropionimidate. No alterations in the interactions between intranucleosomal histone proteins resulted from digestion of the nuclear DNA. There was, however, a diminished extent of cross-linking of histone H1 to itself and to the intranucleosomal histones in DNA-depleted nuclei. The interactions of a group of nonhistone proteins with histone H3 could be monitored by cross-linking through the formation of disulfide bonds caused by oxidation of nuclei with H2O2. These interactions were not markedly affected by treatment of the nuclei with DNAase I. However, differences were observed in the extent of cross-linking of some of these proteins when cross-linking in nuclei from undifferentiated cells was compared to that in nuclei from cells which had been induced to differentiate with dimethylsulfoxide.

Animals↗
PubMed1977

RNA transport in isolated myeloma nuclei. Transport from membrane-denuded nuclei.

Nuclei prepared from MOPC-21 cells were treated with the nonionic detergents Triton X-100 or Nonidet P-40. Chemical analysis revealed that nearly 90% of the nuclear phospholipid was removed by detergent treatment. The membrane-denuded nuclei remained intact with preservation of nuclear pore complexes as demonstrated by electron microscopy. Ribonucleic acid transport from detergent-treated nuclei proceeded at the same rate and to the same extent as in control nuclei. Normal nuclear restriction of nucleic acids was unaltered by removal of the nuclear membranes. The effect of temperature on transport of RNA from freshly isolated myeloma nuclei with intact nuclear envelopes was studied. No temperature transition was associated with the transport process. These data indicate that the transport of macromolecules from isolated myeloma nuclei is independent of the nuclear membrane.

Adenosine Triphosphate↗
PubMed1975

[Nuclei of the medulla oblongata and pons in the red deer and roe. III. Nuclei of the pons and tegmentum pontis].

The material for the studies was obtained from fragments of the brain stem, including the pons Varoli, of 2- and 6-year old red deer and of 2- and 3-year old female roe. The fixed material was mounted in paraffin and cut transversely into 15 micron sections, of which every fifth was examined. Preparations of the alcohol-fixed brain of one red deer and one roe were stained with methylene blue according to Nissl's modified method. Sections of the formalin-fixed brain of the other red deer and roe were stained according to the method of Klüver-Barrera with 0.1% solution of Luxor Fast Blue. Part III describes the structure and localization of the nerve nuclei of the portion of the brain stem under consideration. The following nuclei in the pons Varoli of the red deer and roe were described: nucl. medianus pontis, nucl. paramedianus pontis, nucl. ventralis pontis, nucl. lateralis pontis, nucl. dorso-lateralis pontis, nucl. peduncularis pontis. The nuclei, and especially in the central portion of the pons Varoli, are well developed in the species under discussion. With regard to the tegmentum pontis of the red deer and roe, a description of the structure and topography of the following nuclei is given: nucl. dorsalis tegmenti pontis, nucl. latero-dorsalis tegmenti pontis, nucl. dorsalis raphe, nucl. loci coerulei, nucl. reticularis dorsalis tegmenti pontis, nucl. reticularis ventro-lateralis tegmenti pontis, and nucl. reticularis ventro-medialis tegmenti pontis. The structure and localization of the nuclei of the tegmentum pontis are similar in both species, but the two first nuclei are much better developed in the roe than in the deer. The nucleus loci coeruliei could not be found in the roe.

Animals↗
PubMed1978

The vestibular nuclei in the domestic hen (Gallus domesticus) III. Ascending projections to the mesencephalic eye motor nuclei.

Following injections of horseradish peroxidase in the oculomotor and the trochlear nuclei in the hen, the occurrence of labeled cells was plotted in the vestibular nuclei. The majority of labeled cells was localized in the superior, the medial, and the tangential nucleus. Within the superior nucleus the cells were found mainly caudally, extending medially and ventrally in central areas. In the medial nucleus labeled cells were localized exclusively in its rostral half, mainly in ventrolateral regions. Most, if not all, cells in the nucleus tangentialis project rostrally. In addition, rostrally projecting vestibular cells were found in the cell group A and the rostrolateral part of the descending nucleus. The projection to the oculomotor nuclear complex is from the superior nucleus and the cell group A bilateral but chiefly ipsilateral, from the medial nucleus bilateral, from the tangential nucleus and the rostral pole of the descending nucleus chiefly contralateral. Massive labeling was found in the abducens nucleus, somewhat less in the reticular formation, mainly in the lateral regions of the medial part at the level of the abducens and facial nuclei. Labeled cells were, in addition, found in the deep layers of the optic tectum, and scattered cells in the nucleus raphe. The findings are discussed in the light of what is known of the organization of the vestibular nuclei in the hen and the rostral projection of the vestibular nuclei in mammals.

Abducens Nerve↗
PubMed1978

[Nuclei of the mammillary bodies and their fiber connections in cattle (Bos taurus var. domesticus). I. Nuclei of the mammillary bodies in cattle].

1. In the present neuroanatomic study the topography and cytoarchitectonic of the nuclei of the mamillary body of cattle are described and quantitative-morphologically investigated in 14 series of brains (6 frontal, 4 sagittal and 4 horizontal series, stained by the methods after Nissl, Klüver and Barrera and after Heidenhain). 2. The medial mamillary nucleus of cattle is with an average volume of 47.7 mm3 the largest nucleus of the mamillary body. It contains about 715,000 cells with a cell density of 15,000 cells/mm3 and can cytoarchitectonically be subdivided into a medial part and a lateral part. 3. The median mamillary nucleus is an unpaired and clearly defined nucleus which accounts with an average volume of 16.9 mm3 for a quarter of the whole volume of the nuclei belonging to the mamillary body, however with 11,000 cells/mm3 it shows a relatively small cell density in comparison with the other mamillary nuclei. 4. The lateral mamillary nuclei of cattle are situated in the rostral third of the mamillary body and account for 5.3 per cent of the whole volume of the nuclei. About 28,000 cells with a cell density of 15,000 cells/mm3 were found in each nucleus.

Animals↗
PubMed1976

[Reactions of neurons of the reticular and ventral anterior thalamic nuclei of the cat to electric stimulation of the relay nuclei of the optic thalamus].

Responses of 92 reticular (R) and 105 ventral anterior (VA) thalamic neurons to electrical stimulation of relay nuclei, ventrobasal complex (VB), lateral (GL) and medial (GM) geniculate bodies, were studied in cats immobilized with d-tubocurarine. 72.2% of R and 76.2% of VA investigated neurons responded to VB stimulation, while GM stimulation caused responses only in 15.0% of R and 27.1% of VA neurons and GL stimulation in 10.2% of R and 19.6% of VA neurons. The responses of R-VA neurons to relay nuclei stimulation were expressed, as a rule in excitation. Two types of excited neurons were distinguished: the first group responded to stimulation of afferent inputs by the discharge of 5-15 spikes at a frequency of 250-300 p/s, the second group responded by single action potential. According to peculiarities of their responses, the neurons of the first group are resembling inhibitory interneurons. 2.2% of R and 7.8% of VA neurons responded to relay nuclei stimulation by antidromic spikes. Among R and VA neurons there are cells which respond to stimulation of one, two and even three different relay nuclei. If stimulation of one relay nucleus is followed by a response of R or VA neuron, the preceding stimulation of another relay nucleus, with the time interval between the conditioning and testing stimuli being less than 30-50 ms, induced the inhibition of the response to the testing stimulus.

Animals↗
PubMed1978

Estimation of the mean caliper diameter of cell nuclei. I. Serial section reconstriction method and endothelial nuclei from human lung.

In morphometric studies of lung tissue, accurate determination of the total number of any specific type of cell, such as the endothelial cell, requires knowledge of the shape of the cell nucleus. This knowledge of shape is necessary to calculate the mean caliper diameter, which, in turn, is an indispensible element of the equation for the number of nuclei (therefore cells) per unit volume (NV). Nine human hung endothelial cell nuclei were therfore reconstructed in dental wax from serial sections and were found to be pleomorphic triaxial ellipsoids. Five of these approached an oblate shape. The axes of these nine nuclear models were directly measured and a computer program using numerical integration was written to determine the mean caliper diameters of these ellipsoids. The estimated mean semi-axes of the nine nuclei were (+/-SD) 5.98+/-1.61, 3.61+/-0.70, 1.36+/-0.34; and the estimated overall mean caliper diameter for the total population of human lung endothelial nuclei was 7.97+/-1.27 micrometers.

Cell Nucleus↗
PubMed1975

A comparative study of DNA-dependent RNA polymerases from rat ascites hepatoma cell nuclei and from rat liver nuclei.

DNA-dependent RNA polymerases (EC 2.7.7.6) were extracted and partially purified form the nuclei of rat ascites hepatoma cells (AH-130) induced by 4-dimethylaminoazobenzene. The patterns of RNA synthesis and the properties of these enzymes were compared with enzymes from the nuclei of rat liver. The specific activity of RNA polymerase in the homogenate from the nuclei of AH-130 cells was the same as normal rat liver nuclei. RNA polymerase was solubilized from the homogenate at high ionic strength and separated into two forms by DEAE-Sephadex column chromatography. Enzymatic characterization showed that these enzymes corresponded to RNA polymerase I and II. RNA polymerase I more effectively transcribed native DNA than denatured DNA at low salt concentration, but at high salt concentration RNA polymerase I effectively transcribed denatured DNA. RNA polymerase II more effectively transcribed denatured DNA. In AH-130 cells the activity of RNA polymerase I was 4 to 5 times higher than RNA polymerase II, and in rat liver the activity of RNA polymerase I was 1.5 to 2 times higher than RNA polymerase II. The activity of RNA polymerase I in AH-130 cells may have increased by induction.

Ammonium Sulfate↗
PubMed1979

Differential serotonergic innervation of individual hypothalamic nuclei and other forebrain regions by the dorsal and median midbrain raphe nuclei.

Lesions in the midbrain median but not in the dorsal raphe nucleus significantly decreased the serotonin (5-HT) content of the hippocampus (61%), medial preoptic area (49%), suprachiasmatic nucleus (70%) and anterior hypothalamic area (60%). Electrolytic lesions restricted to either the median or dorsal raphe nucleus produced significant reductions in the 5-HT concentration of the caudate-putamen, anterolateral hypothalamic area (45%) and arcuate nucleus (48--58%). The fall in caudate-putamen 5-HT level was significantly greater after the dorsal (66%) than after the median (24%) raphe lesion. Neither lesion significantly affected the 5-HT content of the posterolateral hypothalamic area, the ventromedial hypothalamic nucleus or the dorsomedial hypothalamic nucleus. Thus, like their differential projections to the caudate-putamen and hippocampus, the mesencephalic dorsal and median raphe nuclei appear to innervate different preoptico-hypothalamic nuclei and areas. Whereas the median raphe nucleus seems to be the primary source of 5-HT fibers to the suprachiasmatic nucleus, anterior hypothalamic area and medial preoptic area, the 5-HT inputs to the anterolateral hypothalamic area and arcuate nucleus appear to derive from both the dorsal and median raphe nuclei.

Animals↗
PubMed1976

Sanded nuclei in hepatitis B: eosinophilic inclusions in liver cell nuclei due to excess in hepatitis B core antigen formation.

In confirmation of earlier descriptions by Huang et al. (Huang S-N, Millman I, O'Connell A, Aronoff A, Gault H, Blumberg BS: Am J Pathol 67: 453, 1972) nuclear eosinophilic inclusions due to excess HBcAg particles have been identified in cases of chronic hepatitis B virus infection. As the euchromatin space of affected nuclei is "sanded" by numerous core particles with concomitant dissolution of the chromatin network, spiky, finely granular, and eosinophilic inclusions without a limiting membrane become visible in hematoxylin and eosin-stained paraffin sections. These HBcAg inclusions stain greyish pink with chromotrope aniline blue and are negative for orcein, the periodic acid-Schiff reaction, and the Feulgen reaction for DNA. Sanded nuclei were detected, although not always and only few in number, exclusively in HBAg-positive patients when a focal (as in chronic aggressive hepatitis) or a generalized core formation (as in immunosuppressed kidney transplant recipients) could be demonstrated by electron microscopy or immunofluorescence. Therefore, the positive finding of sanded nuclei in a persistent hepatitis B virus infection indicates an excessive core formation the extent of which should be verified by specific methods.

Cell Nucleus↗
PubMed1978

Release of dopamine in both caudate nuclei and both substantia nigrae in response to unilateral stimulation of cerebellar nuclei in the cat.

The effects of unilateral focal electrical stimulation of the deep cerebellar nuclei on the activity of the nigrostriatal dopaminergic neurons on both sides of the brain were examined in halothane anaesthetized cats. For this purpose, push-pull cannulae were inserted into both caudate nuclei and both substantia nigrae, and the release of [3H] dopamine ([3H]DA) continuously formed from [3,5-3H]L-tyrosine was estimated in superfusates. The unilateral electrical stimulation of the right cerebellar dentate nucleus induced a long-lasting increase in the release of [3H]DA in the left caudate nucleus and a simultaneous decrease in the release of [3H]transmitter in the right caudate nucleus. These changes were associated with opposite fluctuations in the release of [3H]DA from the corresponding substantia nigrae. Thus, the electrical stimulation of the right dentate nucleus induced a pronounced decrease in the release of the [3H]-amine in the [3H]transmitter in the corresponding substantia nigra, whereas the activity of the contralateral substantia nigra, whereas the release in the ipsilateral substantia nigra was simultaneously increased. In contrast, the unilateral electrical stimulation of the right cerebellar fastigial nucleus resulted only in an increased release of [3H]DA in the ipsilateral (right) caudate nucleus, associated with a decreased release of the [3H]transmitter in the corresponding substantia nigra, whereas the activity of the contralateral (left) dopaminergic system was not significantly affected. These results support a direct functional interaction between the cerebellum and the basal ganglia. They also suggest that the release of DA from dopaminergic axonal terminals is inversely correlated to the extent of the transmitter release from dendrites.

Adrenergic Fibers↗
PubMed1978

[RNA transport from rat liver cell nuclei in vitro. Release of rapidly labeled RNA from isolated nuclei in a cell-free system in the presence of RNAse affectors].

A cell-free system was developed and characterized, which supported RNA release from isolated rat liver cell nuclei. The RNA release in the system seemed to be dependent on the presence of ATP as an evergy source and of dialized cytosol as far as on the temperature level in the incubation mixture. In vitro effects of a number of RNase affectors from cytoplasm and of related exogenous compounds on the RNA release were studied. It was shown that RNase inhibitors such as heparin, PVS and rat liver cytoplasmic RNA were capable to stimulate the RNA release, while the natural inhibitor from liver cytosol failed to influence the RNA relase. Spermidine and PCMB lowered the rate of RNA release from nuclei. The results are discussed in connection with possible role of nuclear RNases and cytoplasmic factors in nucleocytoplasmic transport of RNA.

Adenosine Triphosphate↗
PubMed1978

Dorsal column nuclei in a prosimian primate (Galago senegalensis). II. Cuneate and lateral cuneate nuclei: morphology and primary afferent fibers from cervical and upper thoracic spinal segments.

The morphology and brachial cord primary afferent projections of the cuneate and lateral cuneate nuclei have been studied in the lesser bushbaby. The cuneate nucleus was divided into three regions. From caudal to rostral these were the large cell, cell column and rostral regions. Primary afferents from C2, C4, C6, C7, C8, T1 and T3 terminated within distinct partially overlapping terminal zones in the ipsilateral large cell and cell column regions of the cuneate nucleus (CN) and the lateral cuneate nucleus (LCN). Segmentotopic was the greatest in the rostal region of the CN due to a more diffuse projection pattern. In the LCN, the transverse terminal fields appeared as curved mediolaterally oriented laminae. In each case, ascending fibers of passage from C4, C6, and C7 in the cuneate fasciculus were organized so that two distinct fiber laminae were present. The separation of fibers and the formation of the two ascending laminae were completed either within two segments rostral to their respective level of entry (for C6 and C7 lesions) or in the caudal medulla (for C4 lesion). For each of these segments, the laminae consisted of a small dorsomedial one and a large lateral one. The organization of primary afferents from one segment into two ascending fiber laminae in the cuneate fasciculus was reflected in a differential termination pattern within both the CN and LCN. The results of this study were discussed relative to earlier anatomical and physiological studies on the DCN in other animals.

Afferent Pathways↗
PubMed1978

[Concentration of acid proteins in the nuclei of rat hypothalamic neuron and glial cell nuclei during cold adaptation].

By means of two-wave length cytospectrophotometry the acid protein content per cell was determined in the nuclei of the neurons and their glial satellite cells of the medial peroptic area and the supraoptic nucleus of the hypothalamus of rats kept at 2--4 degrees C for 1, 3, 7, or 15 days (adaptation to cold). This colling resulted in an initial decrease in the nuclear acid protein content in the whole neuron-neuroglia system of the medail preoptic area with a gradual restoration to the normal by the 15th day of constant cooling. In the glial cells of this area the acid protein content increased temporarily above the control level before the restoration to the normal. A gradual accumulation of acid proteins and its following restoration to the control level was revealed in the neuron-neuroglia system of the supraoptic nucleus. By the 15th day of the adaptation to cold the content of neuronal and glial acid proteins of this nucleus became somewhat lower than in the control.

Acclimatization↗
PubMed1978

[Transport of RNA from rat liver cell nuclei in vitro. Effect of superoxide dismutase on the release of rapidly labeled RNA from isolated nuclei].

Purified superoxide dismutase from beaf and rat liver cytosol was found to inhibit in vitro a release of the newly synthesized poly(A)-containing RNA from isolated hepatocyte nuclei in a cell-free system. The inhibition was concentration-dependent. Similar effect was observed with Cu2+ and coppertyrosine complex, which possess SOD-like type catalytic activity. The effectiveness of the complex and of Cu2+ however was an order smaller than that of SOD. The inhibitory effects of SOD and the two other copper-containing compounds could be abolished by potassium cyanide and reduced glutathione as far as by gomologous cytosol. Catalase failed to effect the RNA release. Although serum albumin itself did not affect release of RNA it was capable to abolish the inhibitory effects of Cu2+ and of copper-tyrosine, but not that of SOD. Possible mechanisms for the inhibitory effect of SOD on RNA transfer across the nuclear envelope are discussed.

Animals↗