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Endogenous digitalis-like substance (EDLS) is a newly discovered humoral agent which causes sodium-diuresis. EDLS is well known to have inhibitory activity to Na+,K(+)-ATPase and cross-immunoreactivity to digoxin antibody; however, its precise chemical structure has not yet been determined. We had previously developed a histochemical technique for EDLS, i.e., digoxin-immunohistochemistry, and demonstrated that EDLS was produced in the hypothalamic neurons. In the present study, the distribution of EDLS-containing neurons in the hypothalamus of dog and macaque was investigated using this technique, because anti-EDLS antibody cannot be obtained yet. In both species, EDLS neuronal somata were mainly localized in the paraventricular nucleus and the supraoptic nucleus and its accessory nuclei. A number of somata were also scattered in the other hypothalamic areas. The processes of these neurons ran from the area where the somata were located, through the lateral and basal area of the hypothalamus, to the infundibulum. These nerve fibers with varicosities were associated with the primary capillaries of hypophysial portal veins. A few immunopositive nerve fibers were also seen in the pituitary posterior lobe of both species. Intensive immunoreactivities were observed in the subfornical organ and organum vasculosum laminae terminalis. There were no differences between dog and macaque.

Distribution of gastrin-releasing peptide (GRP)-containing peripheral nerve fibers in the respiratory organs, digestive tracts and hearts of rat, monkey and human was studied with immunohistochemical method. In the trachea, GRP-immunoreactive nerve fibers were observed in the lamina propria and surrounded ducts and acini of tracheal serous glands with a basket-like appearance. In the lung, immunoreactive nerve fibers were scattered in the lamina propria of bronchi and bronchioles, and also the adventitia of veins. In the digestive organs, such as esophagus, duodenum and jejunum, numerous GRP-immunoreactive nerve fibers were distributed in the lamina propria and muscle layer; especially in the former layer where they were seen running up to the apical part of villi. GRP-containing nerve bundles and branched fibers were also observed in the atrial muscle layer. These results gave a morphological basis to future studies of the functional significance of GRP on autonomic mechanisms.

The parietal cortex and dorsal hippocampus of adult rats were unilaterally ablated. One and 3 months after this operation, changes in serotonergic fiber distribution in the forebrain were studied immunohistochemically. At 1 month, increased numbers of serotonergic fibers were seen in the cingulate cortex and the medial and lateral septal nuclei of the lesioned side. This increase continued to 3 months in the ipsilateral cingulate cortex. In the present study, two different processes of serotonergic fiber collateral sprouting were noted. Plastic changes in serotonergic fibers in the ipsilateral septal nuclei and cingulate cortex may be attributable to the collateral sprouting underlying reactive synaptogenesis and the pruning effect, respectively.

1. In situ hybridization histochemistry permits the study of specific mRNAs of neuropeptides, enzymes involved in the synthesis of neurotransmitters, receptors and proteins associated with glial cells in nervous tissue. 2. The central and peripheral nervous systems are composed of heterogeneous elements and specific regulatory mechanisms occur in specific cells. 3. This review will focus on the localization and regulation of different mRNAs in the nervous system from Drosophila to human, as revealed by in situ hybridization histochemistry.

The peroxidase-antiperoxidase technique was used to study the ontogenesis of serotonin-containing neurons in fetal, neonatal and adult rats. Serotonin-containing neurons were first detected in a rat embryo of crown-rump length (CRL) 5 mm, bilaterally distributed in the ventral metencephalon near the isthmus rhombencephali. Serotonin fibers were first detected in CRL 6 mm embryos. There was a rapid increase in serotonin-immunoreactive neurons of embryos of 7–8 mm CRL. Serotonin neurons appeared initially as independent, bilateral groups of neurons, but as early as CRL 16 mm, the adult mid-line distribution was present, while the neurons that occurred as single groups in the adult already existed as single groups or at least were only partially connected across the mid-line. A continuous distribution of serotonin neurons was observed in the mesencephalic and pontine reticular formation from CRL 13 mm to the adult stage. It is suggested that the rapid increase in serotonin neurons at 7 and 8 mm CRL is associated with the completion of mitosis which occurs at this time.

Immunohistochemistry was used to localize brain natriuretic peptide in the porcine spinal cord and to compare it with that of atrial natriuretic peptide, substance P, calcitonin gene-related peptide and [Met]enkephalin. Brain natriuretic peptide-immunoreactive varicose fibers were observed in lamina I and the inner portion of lamina II of the dorsal horn. Semiquantitative analysis showed that the highest density of brain natriuretic peptide-immunoreactive varicosities was in the lumbosacral and coccygeal segments. The distributional pattern of brain natriuretic peptide-immunoreactive nerve fibers in the spinal cord was unique and quite distinct from that of the other neuropeptides studied. These neuroanatomical findings suggest that brain natriuretic peptide may play a role in the regulation of nociceptive processing in the spinal cord, either alone or with bioactive substances.

The magnetic properties of Y2Fe14-xCoxB (0 ⩽ x ⩽ 12) and Y2Fe14-xMnxB (0 ⩽ x ⩽ 5) have been investigated by 57Fe Mossbauer spectroscopy. Single crystalline samples of Y2Fe14-xCoxB were used in magnetization measurements. The magnetic hyperfine field of Fe in Y2(Fe, Co)14B decreases monotonically with increasing Co content, and the value obtained are not entirely coincident with those estimated from the magnetization. The results are discussed in connection with the rigid band model and the magneto-volume effect. Mn substitution considerably reduced both of the magnetization and the Curie temperature. It was found that the Mn atom has no magnetic moment and take no part in magnetic interaction.