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Biomedical subjects

G Ju

Publications and source records attributed to G Ju.

148 records · Page 9Linked to original sources
PubMedDate not supplied

Evidence for hypothalamic paraventricular nucleus as an integrative center of neuroimmunomodulation.

It has been well documented that the medial parvocellular subnucleus of the hypothalamic paraventricular nucleus (PVN) participates in immune regulation by releasing corticotrophin-releasing hormone (CRH), which triggers the hypothalamus-pituitary-adrenal axis, leading to immunosuppression. Little is known about other possible influences of PVN on immunomodulation. Evidence, however, has been accumulating recently, indicating possible involvement of other subnuclei of this nucleus. By using the c-fos technique, the present study investigated the neuronal groups of the PVN that were activated in response to intracerebroventricularly administered IL-1 beta. In addition to strong Fos expression in the dorsal part of medial parvocellular subnucleus of the PVN, where CRH neurons are located, two more neuronal groups were found to express Fos protein. One of which was the oxytocin-immunoreactive magnocellular neurons, mainly concentrated in the anterior and medial magnocellular subnuclei of the PVN. The magnocellular PVN subnuclei are known to project to, and release their hormones, in the posterior pituitary. Another group of Fos-immunoreactive neurons were found in the brainstem and spinal cord projecting area of the PVN. By combining retrograde tracing technique and Fos immunohistochemistry, it was proved that many of the spinal cord projecting PVN neurons were activated following IL-1 beta administration, through which the spinal cord sympathetic outflow might be regulated. The present study indicates that the hypothalamic PVN may serve as an integrative center for immunomodulation via three channels, i.e., the CRH and oxytocin neuroendocrinological and the PVN-spinal cord sympathetic neural channels.

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Substance P-immunoreactive nerve fibres in the pars distalis of the anterior pituitary of macaques.

The anterior pituitary glands of Macaca mulatta and M. assamensis were stained with antiserum against substance P (SP). A substantial amount of SP-immunoreactive (ir) nerve fibres with numerous varicosities were found in the pars distalis of the anterior pituitary. They were located in the median part of the gland and were distributed mainly in its dorso-posterior region. The great majority of the varicosities were found to be related to the glandular tissue, although some apparently were located along the walls of the blood sinuses. In addition, many SP-ir cells, mostly large and oval, were distributed at the periphery of the gland. In areas where both SP-ir nerve fibres and cells were present, many cells were found to be in close proximity to the nerve fibres.

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Immunohistochemical studies on cholecystokinin (CCK)-immunoreactive neurons in the rat using sequence specific antisera and with special reference to the caudate nucleus and primary sensory neurons.

In the present immunohistochemical study the occurrence and distribution of CCK-immunoreactive neurons were analyzed in the brain, spinal cord and sensory ganglia using sequence specific antisera. Thus, antibodies directed towards the C-terminal portion of CCK-33, to the N-terminal portion of CCK-8 and to the mid portion of CCK-33 as well as monoclonal antibodies were used. For comparison antisera raised against calcitonin gene-related peptide (CGRP), tyrosine hydroxylase (TH) and 5-hydroxytryptamine (5-HT) were used. Untreated, colchicine treated, 6-hydroxydopamine (6-OH-DA) treated and ibotenic acid treated rats were analyzed. The results indicate that most CCK systems in the rat central nervous system contain genuine CCK. These include, for example, the hippocampal formation, the hypothalamus, several subcortical forebrain areas, the ventral mesencephalon, nucleus tractus solitarii, some neurons in the ventral medulla oblongata as well as local and possibly descending neurons in the spinal cord. An exception was primary sensory neurons in which CCK-like immunoreactivity (LI) could only be demonstrated with C-terminally directed antisera and probably represents cross-reactivity with CGRP or a similar peptide. The central branches of such primary afferents were found both in the dorsal vagal complex, in the spinal trigeminal nucleus and in the dorsal horn of the spinal cord. Special attention was focused on CCK-LI in mesencephalic dopamine neurons and in their projection areas including nucleus accumbens, tuberculum olfactorium and particularly the caudate nucleus. In the latter structure CCK-LI exhibited a heterogenous pattern probably representing fibres of different types and origin. Thus, CCK-LI coexists with dopamine in two anatomically and morphologically distinguishable systems, one located in the periventricular area, increasing in size in the caudal direction to occupy most of the cauda, and a second system consisting of very fine dots in the medial half of the caudate nucleus. These two fibre types disappeared after 6-OH-DA treatment. A third system consisted of strongly fluorescent patches distributed at all levels of the caudate nucleus, mainly in its medial half. A diffuse, weakly fluorescent network of CCK-positive fibres was also found over the entire caudate nucleus. The latter two systems did not disappear after 6-OH-DA. Finally, local CCK-positive cell bodies were seen in small numbers, mainly in the ventral aspects of the caudate nucleus.(ABSTRACT TRUNCATED AT 400 WORDS)

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