Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 2005-2009  (1)
  • 1980-1984  (9)
  • 1
    ISSN: 1432-0878
    Keywords: Hypothalamus (rat) ; Differentiation ; Transplant ; Histofluorescence ; Immunocytochemistry ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Hypothalamic tissue from 16 to 18-day fetal rats was transplanted onto the choroidal pia overlying the superior colliculus in adult female rats. After survival periods of 2 weeks to 19 months, brains containing transplants were processed for monoamine fluorescence histochemistry, immunohistochemistry for three neuropeptides (LHRH, somatostatin, neurophysin), or for autoradiography in ovariectomized hosts that received [3H] estradiol. Most of the transplants survived and retained or increased in size; 14 of 25 transplants examined by fluorescence histochemistry were found to contain median eminence-like structures. In almost all of the transplants that were stained for neuropeptides, beaded processes and occasional cell bodies were observed. Although immunoreactive fibers were found near blood vessels, no palisade arrangement typical of the normal median eminence was evident. Each of the hypothalamic transplants on which steroid autoradiography was performed contained clusters of estrophilic neurons, the intensity of labeling of which was comparable to that seen in the host hypothalamus. These results indicate that many characteristic morphological and chemical features of the hypothalamus, which are not evident in the 16 to 18-day fetus, are elaborated in transplants during the survival period in the host. Transplantation of fetal hypothalamus to adult choroidal pia thus appears to be a valuable approach for studying the factors, humoral or neural, that regulate the differentiation of this brain region.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 300 (1982), S. 648-649 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Hypothalamic nuclei were removed from frozen, 300-jjim thick brain sections, using hollow stainless steel cannulas, 500 or 1,000 |xm in diameter. We pooled tissue from three ovariec-tomized or castrated rats (CD-1 strain, Charles River Biological Laboratories; 150-180 g) for an assay. For ...
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Female rats ovariectomized for 5-7 days were fitted with 5-mm silastic capsules containing oestradiol, which produced physiological levels of the hormone in serum4. For behaviour, each female was assigned to a separate mating group of 5-10 animals. Females received 10 mounts by male rats 24 h after ...
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 291 (1981), S. 610-610 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] TESTOSTERONE acts during a limited period of perinatal development in male mammals to influence permanently the development of reproductive behaviour and neuroendocrine function, as well as to promote development of the reproductive tract. Although for some years the brain, and not the pituitary, ...
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: We measured the distribution of molecular forms of acetylcholinesterase (AChE) in muscles of a song bird, the zebra finch, and found a pattern similar to those reported in other vertebrates. As in other species, the most rapidly sedimenting form of the enzyme decreases to barely detectable levels following denervation. In the muscles of the syrinx, castration causes a large decrease in AChE activity, but has little or no effect on the relative abundance of AChE forms. This suggests that the number of AChE catalytic sites is changing without affecting the distribution of catalytic sites among the molecular forms. This is in marked contrast with the effect of denervation in the syrinx, which causes changes in the distribution of activity, as well as in total activity.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Addition of vasoactive intestinal peptide (VIP) to brain homogenates increased the activity of choline acetyltransferase (ChAT) but not that of acetylcholinesterase or glucose-6-phosphate dehydrogenase. Activity of ChAT was increased in the anterior hypothalamus and in the dorsal and ventral hippocampus, but not in the parietal cortex or posterior hypothalamus. Increased activity occurred rapidly after VIP addition to homogenates and was maximal at 10 -7M concentration. Kinetic analysis indicates that the Vmax of the enzyme is increased and the Km for choline, but not acetyl-coenzyme A, is decreased in the presence of VIP. Results support a possible VIP-cholinergic interaction in the CNS.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Cytosolic dexamethasone (DEX) binding sites were studied in the Wallerian-degenerating rat optic nerve (ON), a tissue that is rich in neuroglial cells but devoid of neuronal perikarya and processes. For comparison, hippocampal (HI) and anterior pituitary (AP) cytosols were studied in parallel. Binding sites in these three tissues were found to be quite similar in almost all respects. The sites have a high affinity for DEX (KD= 2.5–3.5 nM), are present at a high concentration (Bmax= 360–365 fmol/mg cytosol protein), and possess a binding specificity typical of glucocorticoid receptors in other organs. Most experiments supported the assumption of a single DEX-binding species in each tissue. Saturation analyses consistently yielded linear Scatchard plots over the range of DEX concentrations tested. Density gradient centrifugation in each case revealed a single peak with a sedimentation coefficient of 7–8S at low ionic strength and 4–4.5S in the presence of 0.3 M KCl. Isoelectric focusing similarly localized most of the binding in each cytosol to a single large peak with an isoelectric point of approximately 6.0. Dissociation rate determinations, on the other hand, suggested the possibility of two different binding sites in each tissue. These studies show that glucocorticoid binders present in cells of the ON possess the same characteristics as the cytoplasmic receptors found in HI, AP, and other recognized glucocorticoid target tissues.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Biochemical evidence suggests that neuroglia are responsive to glucocorticoids, yet previous studies of glucocorticoid localization have typically failed to demonstrate significant uptake by neuroglial cells. To further investigate this problem, we measured glycerol-3-phosphate dehydrogenase (GPDH) activity and glucocorticoid receptor binding capacity in normal rat optic nerves and in those undergoing Wallerian (axonal) degeneration. Binding studies were also performed on hippocampus and anterior pituitary for comparison purposes. Normal optic nerve preparations possessed a high level of GPDH activity that was glucocorticoid-inducible and that increased further following axonal degeneration. Antibody inactivation experiments demonstrated the presence of more enzyme molecules in the degenerating nerve preparations. Correlative immunocytochemical studies found GPDH-positive reaction product only in morphologically identified oligodendrocytes, a result that is consistent with the previously reported localization of this enzyme in rat brain. Optic nerve cytosol fractions displayed substantial high-affinity binding of both dexamethasone (DEX) and corticosterone (CORT) that, like GPDH, was elevated approximately twofold in degenerating nerves. Finally, in vivo accumulation of [3H]DEX and [3H]CORT by optic nerve and other myelinated tracts was examined using nuclear isolation and autoradiographic methods. Although neither steroid was found to be heavily concentrated by these tissues in vivo, a small preference for DEX was observed in the nuclear uptake experiments. These results are discussed in terms of the hypothesis that glial cells are targets for glucocorticoid hormones.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: We have examined the ability of various steroids to compete for high-affinity binding of 3H-labeled ligands to catecholamine receptors in membranes prepared from rat cerebral cortex, striatum, and anterior pituitary. Ligands employed were: [3H]WB4101, [3H]prazosin, [3H]yohimbine, and [3H]clonidine (alpha-noradrenergic); [3H]dihydroalprenolol (beta-noradrenergic); [3H]spiperone and [3H]ADTN (dopaminergic). Only the 17β estrogens were effective and only binding of [3H]spiperone and [3H]ADTN in striatum and [3H]WB4101 and [3H]prazosin in cerebral cortex was reduced. Thus putative dopaminergic and alpha1-noradrenergic sites alone appear to recognize estrogens. A slight competitive effect on [3H]spiperone binding to anterior pituitary membranes was also observed. Among the 17β estrogens tested, the most effective in all cases was the catechol estrogen 2-hydroxyestradiol (2-OHE2). The ability of 2-OHE2 (IC50= 20–30 μM) to inhibit ligand binding to alpha1 receptors was comparable to that of norepinephrine (IC50= 10–20 μM), whereas for dopamine receptors in striatum and pituitary 2-OHE2 was an order of magnitude less effective than dopamine (IC30= 12 μM) in reducing binding of 3H ligands. Estradiol-17β and 2-hydroxyestrone were also able to inhibit binding, but the order of steroid potency was different for alpha1 and dopaminergic receptors. Progesterone, testosterone, and corticosterone were without effect in all cases. These results show that there is specificity of steroid interactions with catecholamine receptors in the brain, both in terms of steroid structure and receptor type. The possible relevance of these interactions to neuroendocrine function is discussed.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 10
    facet.materialart.
    Unknown
    London : Henry Stewart Talks
    Keywords: Hormones
    Description / Table of Contents: Contents: Estrogen regulation of female sexual behavior in the rat -- Adrenal steroids and spatial memory -- Steroid hormone metabolism in brain -- Limitation of steroid access -- Rapid non-genomic actions of steroids in brain -- Steroid regulation of signaling pathways -- Steroid hormones have widespread effects on brain structure and function -- Effects of estrogens on synapse formation in hippocampus -- Effects of stress and glucocorticoids on dendritic remodeling in hippocampus -- Sexual differentiation of the brain
    Notes: Animated audio-visual presentation with synchronized narration.
    Pages: 1 streaming video file (27 min.) : digital, mono., SWF file, sd., col.
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...