Immunocytochemical study of angiotensin II cell bodies in the rat thalamus

The distribution of angiotensin II cell bodies in the thalamus of the rat was studied by means of intratissue injections of colchicine and using an indirect immunoperoxidase technique. The densest clusters of immunoreactive perikarya were observed in the nuclei geniculatum laterale, medialis dorsalis, ventralis posterior, centralis lateralis, centralis medialis and anterior dorsalis, whereas the nuclei lateralis posterior, lateralis and geniculatum laterale dorsalis had the lowest density. In other thalamic nuclei, geniculatum mediale, lateralis anterior, paraventricularis and ventralis medialis, the density of angiotensin II cell bodies was intermediate. In all these thalamic nuclei, small, round immunoreactive cells with short processes were observed.

Tyrosine hydroxylase immunoreactivity in a subpopulation of granule cells in the olfactory bulb of teleost fish

The distribution of tyrosine hydroxylase (TH)-like immunoreactivity in the olfactory bulb was studied in three species of teleosts, the tench Tinca tinca, the Mediterranean barbel Barbus meridionalis and the rainbow trout Salmo gairdneri, by using an indirect immunoperoxidase method. The antiserum used displayed a characteristic pattern of immunostaining in the three species, and four main conclusions can be drawn: (1) there is a large population of TH-like positive cell bodies and fibers in the olfactory bulb in fish, mainly in the granule cell and plexiform layers; (2) the immunolabeled cells are identified as granule cells, but only one group of granule cells is positive; (3) specific quantitative variations exist in the pattern of TH immunoreactivity, with use of the same fixative, antibody and localization method, among the three species studied, and (4) the pattern of TH immunoreactivity in the olfactory bulb in teleosts is completely different from that described previously in amniotes.

The cavum septi pellucidi: a fifth ventricle?

The morphological characteristics of the cavum septi pellucidi (CSP) in the rat are described. This structure is formed by a set of cavities generally located in the midline area of the septal region. Into the lumen of the cavities free cells rooted out from the CSP walls were observed. Several layers could be delimitated from the surface of the CSP to the most inner region consisting of connective cells and fibers, and astrocytes. However, no ependymal cells were visualized. According to the morphological data, the CSP wall could have a function of resistance against mechanical tensions that are produced in this brain region. The term 'fifth ventricle' for the CSP seems to be inappropriate.

Immunocytochemical study of Met-enkephalin-like cell bodies in the cat hypothalamus

The distribution of methionine-enkephalin-like cell bodies in the hypothalamus of the cat was studied using an indirect immunoperoxidase technique. Previously, intraventricular or intratissular injections of colchicine were carried out. Met-enkephalin-like neurons were located in all hypothalamic nuclei. The densest clusters of immunoreactive perikarya were observed in the nucleus arcuatus, median eminence, regio praeoptica and perifornical region, whereas the nucleus supraopticus and hypothalamus anterior had the lowest density. In other hypothalamic nuclei the density of methionine-enkephalin (Met-enkephalin) cell bodies was intermediate.