Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous reports on the rat and monkey hypothalamus have revealed a dense noradrenergic innervation within the hypothalamic paraventricular nucleus as assessed by dopamine-beta-hydroxylase immunohistochemistry. These single-label analyses were unable to delineate the cellular structures which receive this catecholaminergic innervation. Double-label preparations in the rat hypothalamic paraventricular nucleus have demonstrated synaptic interactions between noradrenergic varicosities and magnocellular neurons. However, the density and distribution of varicosities contacting chemically identified magnocellular neurons have not been assessed at the light or electron microscopic level. In this report, single-label immunohistochemistry was used to assess the morphology and distribution of vasopressin- and oxytocin-immunoreactive neurons within the macaque hypothalamic paraventricular nucleus. In addition, double-label immunohistochemistry was combined with confocal laser scanning microscopy to quantify the number of dopamine-beta-hydroxylase-immunoreactive varicosities in apposition to magnocellular neurons expressing vasopressin or oxytocin immunoreactivity. The morphology of chemically identified neurons was also compared to magnocellular neurons in the monkey hypothalamic paraventricular nucleus which were filled with Lucifer Yellow in order to assess the somatodendritic labeling of the immunohistochemical preparation. Qualitative assessment of immunohistochemically identified magnocellular cells indicated that vasopressin- and oxytocin-containing neurons are observed throughout the rostrocaudal extent of the monkey hypothalamic paraventricular nucleus, demarcating this structure from the surrounding anterior hypothalamus. The distribution of the two nonapeptides is complementary, with vasopressin-immunoreactive neurons having a greater somal volume and located in a more medial aspect of the mid and caudal hypothalamic paraventricular nucleus relative to oxytocin-immunoreactive perikarya. For the double-label preparations, a series of confocal optical sections was assessed through the total somal volume of vasopressin- and oxytocin-immunoreactive neurons along with the corresponding dopamine-beta-hydroxylase-immunoreactive varicosities in the same volume of tissue, generating a varicosity-to-neuron ratio which was further characterized morphologically to assess afferent input to the soma and proximal dendrites. Quantitative analysis revealed that vasopressin-immunoreactive neurons received approximately two thirds of their dopamine-beta-hydroxylase-immunoreactive varicosities in apposition to the proximal dendrites and one third in apposition to the somata. Furthermore, vasopressin-immunoreactive neurons received a greater innervation density than oxytocin-immunoreactive neurons, which did not have a differential distribution of varicosities on the proximal dendrites and somata. The distribution of dopamine-beta-hydroxylase-immunoreactive afferents on magnocellular neurons in the hypothalamic paraventricular nucleus may reflect a physiological role of this circuit in terms of preferential release of vasopressin from magnocellular neurons upon noradrenergic stimulation.
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PMID:Noradrenergic innervation of vasopressin- and oxytocin-containing neurons in the hypothalamic paraventricular nucleus of the macaque monkey: quantitative analysis using double-label immunohistochemistry and confocal laser microscopy. 820 Oct 25

In the supraoptic nucleus (SON), the incidence of conducting gap junctions (gjs), as indicated by dye coupling, is low in cycling females, but dramatically elevated in nursing mothers. Functionally, this is consistent with the well-established presence of synchronous milk ejection bursts among oxytocin neurons only in the lactating rat. In situ hybridization data, however, revealed elevated gj mRNA expression on the last day of pregnancy, a time when burst firing by putative oxytocin neurons is absent. Using Lucifer Yellow dye coupling, we determined the incidence of high conductance gjs in SONs of proestrous, immediately prepartum, postpartum non-lactating, lactating day 1, and lactating day 9-10 rats. Results indicate that coupling incidence is high only at times when milk ejection bursts are known to occur, and that the elevated gj mRNA expression seen on the last day of pregnancy does not indicate conducting gjs. It is suggested that gj conductance states, but not gj expression, are modulated by plasma estradiol titers.
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PMID:Peripartum interneuronal coupling in the supraoptic nucleus. 1191 68

The paraventricular nucleus (PVN) of the hypothalamus is an interesting structure with diverse functions due to its different neuronal populations, neurotransmitters, and projections to other central nervous system structures. The PVN is a primary source of oxytocin (OT) in the central nervous system. In fact, a direct PVN projection to the spinal cord has been demonstrated by retrograde and anterograde tracers, and more than the 50% of this projection is oxytocinergic. This OT descending projection is proposed to be an endogenous system that controls the nociceptive information arriving at the spinal cord. However, we have no information about the specific organization of the OT descending innervations to the different spinal cord segments. The aim of the present study was to determine whether the projecting PVN neurons arrive at cervical regions and then continue to lumbar regions. That is, we sought to establish if the OT projecting cells have a topic or a diffuse projection in order to obtain histological data to support the endogenous OT diffuse mechanism of analgesia described elsewhere. With this purpose in mind we combined the OT immunohistochemistry technique with retrograde neuronal tracers in the spinal cord. We applied Diamidino Yellow (DY) for the superficial dorsal horn cervical segments and True Blue (TB) for the lumbar segments. Data were collected from eight rats with well-placed injections. We only used the animals in which the tracer deposits were confined to superficial layers I and II of the dorsal horn. A mainly ipsilateral projection was observed, but stained neurons were also observed in the contralateral PVN. A large fraction of the stained PVN cells was doubled labeled but some were single labeled. Combining the retrograde tracer techniques and the OT detection procedure, we observed triple-labeled neurons. The present results demonstrate that PVN neurons send collaterals at least to the superficial cervical and lumbar segments of the dorsal horn of the spinal cord. Moreover, some of these stained cells use OT as a neurotransmitter. These results are of great relevance since they demonstrate that the PVN plays an important role in the somatosensorial system, and they support anatomic evidence of an endogenous mechanism involved in analgesia. Finally, we also describe median raphe nucleus double-labeled cells (DY+TB) signaling diffuse descending projections for this largely studied nucleus that are involved in endogenous analgesia.
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PMID:Branched oxytocinergic innervations from the paraventricular hypothalamic nuclei to superficial layers in the spinal cord. 1759 11


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