Showing papers on "Area postrema published in 1973"

Two sites of cardiovascular action of angiotensin II in the brain of the dog.

Abstract: 1. Infusion of angiotensin into both vertebral arteries or into a lateral cerebral ventricle of dogs anaesthetized with morphine-chloralose elicited a centrally mediated rise in blood pressure. 2. Heat coagulation of the area postrema and immediately adjacent structures abolished the pressor response to infusion of angiotensin into the circulation of the vertebral arteries, but did not alter the pressor response when the peptide was delivered into a cerebral lateral ventricle; transection of the midbrain eliminated the latter response but not the former. 3. It is concluded that there are at least two areas in the dog9s brain that respond to angiotensin by inducing a raised blood pressure.

Cellular localization of the uptake of 5-hydroxytryptamine in the area postrema of the rabbit after injection into a lateral ventricle.

Abstract: 1. The cellular localization of 5-hydroxytryptamine (5-HT) was investigated in the area postrema of the rabbit after intraventricular injection under different experimental conditions. 2. 5-HT was found to be accumulated in different parts in and near to the area postrema, e.g. in glial cells, dorsal surface of the area postrema and ependyma of the central canal. 3. The concentrations of 5-HT and 5-hydroxy indol-3-yl acetic acid (5-HIAA) were measured in different parts of the brain and CSF in control and in 5-HT treated animals with and without pargyline pretreatment. Intraventricular injection of 5-HT increased the concentration of 5-HT and 5-HIAA in the brain and in the CSF; pretreatment with pargyline further increased the concentrations of 5-HT but decreased the concentration of 5-HIAA.

Mast cells and postnatal topographic anomalies in mammalian subfornical body and supraoptic crest.

Abstract: In the central nervous system of 22 animal species, mast cells occur (1) in both the subfornical body and the supraoptic crest in chimpanzee, stumpatailed monkey, agouti and flying squirrel and in cynomolgus monkey from 1 day of age; (2) in the subfornical body in paca, ground squirrel, woodchuck and prairie dog; and (3) in the supraoptic crest in cats from 2 days of age through the fourth month, and capybara. The medial habenular nucleus and the area postrema contain mast cells in many of the animals, but differences in number with species and with age do not follow the same pattern as in the above regions. Not infrequently, the thalamus has a considerable number of mast cells, and occasionally other regions, such as the dentate nuclei and the medulla oblongata, have a few mast cells.

LCM Disease of the Adult Rat: Morphological Alterations of the Brain

Abstract: LCM virus, strain WE, multiplies readily in the brain of young adult Sprague-Dawley rats with maximum titers of close to 108 ID50/g of tissue, which are reached by day 5. Five to 6 days after the intracerebral inoculation of 106 mouse ID50 clinical signs develop which closely resemble the ones seen in mature mice infected via the brain. The morphological alterations, too, are similar in both species, although in the rat they are more widespread, involving parts of the brain which remain essentially normal in the mouse. In the rat, inflammatory reactions are found in the meninges, predominantly in the basal regions, as well as in circumventricular organs, such as plexus chorioidei, subfornical organ, area postrema, organum vasculosum laminae terminalis, and median eminence. In severe cases, the ventricular ependyma too is largely destroyed, and beneath the ependyma distentions of the intercellular spaces and structural changes of myelinated axons occur. Here, perivascular round cell infiltrates dominate the picture, whereas in other areas, such as the hypothalamus, the thalamus, and the cerebellar nuclei, a diffuse distribution of inflammatory elements is accompanied by a moderate glial reaction.

Phycomycetes and mast cells in hypependymal cysts of the area postrema in Macaca arotoïdes

Abstract: The stumptailed monkey (Macaca arctoides) was found to have, in and next to the area postrema, hypependymal cysts, which in one animal harbored a fungus belonging to the Phycomycetes. Invasion of the brain by such a fungus has not previously been described in primates. The predominantly non-septate hyphae were appended to mast cells, which occur in large number in the area postrema of this animal species. While arterial thrombosis with scattered hyphae and mast cells had developed in the tela of the third ventricle, the brain was free of necrosis or granulomatous reaction. Site of origin and predisposing factors were not disclosed.

On the Ultrastructure of the Organon Vasculosum Laminae Terminalis (OVLT) of the Rat with Special Reference to its Vessels. Summary

Abstract: The organon vasculosum laminae terminalis (OVLT) along with the neurohypophysis, subfornical organ, area postrema, subcommissural organ, epiphysis and choroid plexus belongs to the group of circumventricular organs, representing a special differentiation of all, i.e. glial, ependymal, neuronal and mesenchymal tissue portiions of a cerebral wall area which in the development stages ahs remained relatively thin-the lamina terminalis.