A cell-by-cell analysis of the magnocellular elements in hypothalami of fifty Long-Evans (normal) and Brattleboro (diabetes insipidus) rats was done using the unlabeled antibody enzyme technique (PAP) with primary antisera directed against oxytocin (OXY), vasopressin (ADH), and the neurophysins. The magnocellular neurons of the hypothalamus were found in the supraoptic (SON), paraventricular (PVN), and anterior commissural (ACN) nuclei, a number of accessory nuclei, and as individual cells in the anterior hypothalamic area. SON was divided by the optic tract into the principal part and retrochiasmatic SON. In retrochiasmatic SON a majority of the cells contained vasopressin. Within the principal part of SON oxytocin-producing cells tended to be found rostrally and dorsally, while the vasopressin cells were more common caudally and ventrally. PVN was divided into three subnuclei, the medial, lateral, and posterior subnuclei, on the basis of cellular morphology and peptide content. The magnocellular cells of the medial and lateral PVN were closely packed together and nearly round, while those of posterior PVN were more separated and fusiform in shape with their long axis running in a medio-lateral direction. Medial PVN consisted primarily of oxytocin-producing cells, while lateral PVN was formed by a core of vasopressin-producing cells with a rim of oxytocin cells. Posterior PVN contained largely oxytocin-producing cells. Both ADH and OXY cells were found in the accessory nuclei. In the Long-Evans rat the SON had, on the average, 1443 OXY and 3236 ADH cells; the PVN had 1174 OXY and 976 ADH cells; and the accessory magnocellular groups in the hypothalamus (including the ACN) had 1286 OXY and 552 ADH cells. The Brattleboro strain animal had similar numbers of cells in these nuclei. (The cells which contain ADH in normal animals were identified in the Brattleboro rat as large, neurophysin-negative cells.) Thus, a large fraction of the magnocellular oxytocin- and vasopressin-producing cells in the rat were located outside of the PVN and SON. One accessory cell group in particular, ACN, had 616 OXY cells, or about 50% as many as PVN. In each nucleus the sum of the numbers of OXY and ADH cells was approximately the number of neurophysin cells.

Little information is currently available on the localization of noradrenergic systems in the human CNS. We used quantitative autoradiography with [125I] iodopindolol to examine beta-adrenergic receptors in postmortem human brain. The concentration of beta-receptors was highest in all subfields of the hippocampus, followed by cerebellum, and then thalamic nuclei, basal ganglia, midbrain, and cerebral cortex. Low levels were found in white matter and hypothalamus. This distribution differed from the distribution of beta-receptors reported in membrane homogenates of human brain and also from the distribution of beta-receptors in rat brain determined by autoradiography. The similarities and differences between the distribution of beta-receptors in the human and rat brains may have implications regarding the role of norepinephrine in the CNS of these two species.

This report describes the distribution of neurophysin-containing, estradiol-concentrating neurons in a strain of rat which is congenitally unable to produce vasopressin and its associated neurophysin (the Brattleboro rat). In this strain of rat, all of the neurophysin-containing cells are oxytocin producing. The magnocellular neurons which produce vasopressin in the normal rat are present in their normal numbers and normal locations (Rhodes, C. H., J. I. Morrell, and D. W. Pfaff (1981) J. ) and can be identified as the neurophysin-negative magnocellular neurons.Estradiol-concentrating cell nuclei were observed in magnocellular neurons with neurophysincontaining cytoplasm as well as in magnocellular neurons lacking immunocytochemically detectable neurophysin. The majority of these neurons were found in the paraventricular nucleus (PVN), ventral and medial to its lateral subnucleus, and in the posterior subnucleus of the PVN. There were, in addition, many neurophysin-containing and neurophysin-lacking magnocellular neurons with nuclei which did not concentrate estradiol. Within the PVN, the majority of the neurophysinnegative, non-estradiol-concentrating neurons were in the lateral subnucleus, while the majority of the neurophysin-positive, non-estradiol-concentrating neurons were in the medial subnucleus.Comparison of the results of experiments using homozygous Brattleboro rats with the results of similar experiments using the (normal) parent strain Long-Evans rat suggests that, in the normal animals, there are both oxytocin-and vasopressin-producing neurons which concentrate estradiol. Comparison of these observations with published descriptions of the anatomical distribution of neurons which project to the medulla or spinal cord suggests that many of the oxytocin-.or vasopressin-containing, estrogen-concentrating neurons in the PVN send axons to regions regulating autonomic functions.Estrogen treatment is a stimulus for the release of oxytocin (Yamaguchi et al., 1979) and vasopressin (Skowsky et al., 1979). A decrease in immunocytochem-' This paper is dedicated to the Rev. Dr. Winthrop Brainerd,

The distribution of estrogen-concentrating cells in the rat brain has been previously described in detail as has the distribution of cells containing oxytocin, vasopressin, and their associated neurophysins. This report describes the simultaneous localization of [Η]estradiol by steroid autoradiography and neurophysin by immunohistology in cells in the rat hypothalamus. In the rat, neurophysin-containing cells were found in three major nuclei – the supraoptic nucleus, the paraventricular nucleus (PVN) and the anterior commissural nucleus – as well as in a number of accessory nuclei and as individual cells in the anterior hypothalamic area. Of these, only the PVN has appreciable numbers of cells which both concentrate estradiol and contain neurophysin. Within the PVN these cells are found predominantly in the posterior subnucleus.

The effect of water deprivation or estrogen treatment on the oxytocin content of rat hypothalamic cells was examined using a quantitative immunohistological technique. Oxytocin-containing cells were visualized using the immunoperoxidase technique of Sternberg and a primary antiserum directed against oxytocin. The optical density of the darkest 3.2 micrometer diameter spot in the cytoplasm of a cell was used as a measure of the oxytocin content of that cell. Water deprivation produced a significant decrease in anti-oxytocin staining in the anterior commissural nucleus of males and females. There was a similar decrease in the paraventricular nucleus of males, but not in the paraventricular nucleus of females or the supraoptic nucleus of either males or females. Estrogen treatment of ovariectomized female rats produced a fall in anti-oxytocin staining in the anterior commissural, but not paraventricular or supraoptic nuclei.