Colocalization Of Neuropeptide Y Research Articles

Нейрохимические особенности нейропептид-Y-ергических энтеральных нейронов подслизистого сплетения тонкой кишки в постнатальном онтогенезе

Neuropeptide Y (NPY) plays an important role in the nervous system, including the regulation of vascular tone and gastrointestinal secretion, has a direct inhibitory effect on intestinal motility and secretion. Colocalization of NPY with the enzyme for the synthesis of acetylcholine - choline acetyltransferase (ChAT), neuronal NO synthase (nNOS), vasoactive intestinal peptide (VIP) and calcium-binding protein calbindin (CB) was detected in the neurons of the submucous plexus of the small intestine of rats from the moment of birth until old age using immunohistochemical method of double labeling with antibodies and fluorescence microscopy. From the moment of birth, all NPY-immunoreactive neurons colocalize ChAT. Most of NPY-containing neurons also contain VIP and CB. In aged rats, the percentage of NPY-immunoreactive neurons containing CB, VIP, and ChAT decreases. In young rats from newborns to 20-day-old as well as in aged rats, nNOS is detected in NPY-positive neurons. Thus, at the early stages of ontogenesis and in the senescence, the enteric metasympathetic NPY-immunoreactive submucous neurons contain a wider range of neurotransmitters when compared to adult animals.

Neuropeptide Y type 1 receptors are expressed in pre‐autonomic neurons in the hypothalamic paraventricular nucleus

We recently demonstrated that exogenous and endogenous Neuropeptide Y (NPY) decreases sympathetic nerve activity and baroreflex function via an action on Y1 receptors (Y1R) in the hypothalamic paraventricular nucleus (PVN). However, whether NPY acts directly on presympathetic neurons projecting to the rostral ventrolateral medulla (RVLM) is unknown. To test this hypothesis, we used immunofluorescence to determine if Y1R are present in PVN neurons that project to RVLM, identified by prior RVLM microinjection of the retrograde tracer cholera toxin subunit B (CTb, 0.25%; List Laboratories). NPY Y1R‐immunoreactivity (ir) (1:100; Santa Cruz; n=4) was found in scattered neurons in multiple PVN parvocellular subdivisions, including the dorsal, medial, lateral, and ventrolateral subnuclei. NPY Y1R‐ir was also prominent in the PVN posterior magnocellular subnucleus. In separate experiments, NPY Y1R‐ir colocalized with vasopressin‐ir (1:800; gift of H. Gainer) in neurons in this region. While no colocalization of NPY Y1R‐ir with CTb‐ir (1:1000; AbCam) was observed in the more rostral PVN (−1.6 mm from bregma), a significant fraction (16–38%) of NPY Y1R neurons in caudal PVN regions (−1.8 to −2.1 mm from bregma) co‐expressed CTb. In summary, NPY Y1R are expressed in PVN neurons projecting to the RVLM, suggesting that NPY acts directly on these neurons to inhibit sympathetic nerve activity and baroreflex regulation. Supported in part by HL088552.

The innervation of the synovium of the knee joint in the guinea pig: an immunohistochemical and ultrastructural study.

The innervation of the knee joint synovial membrane of the guinea pig, i.e., the synoviocyte layer, the subjacent connective tissue and the connective tissue region beneath, was analyzed with immunohistofluorescence and electron microscopy. A screening of the innervation with antibodies against the general axon marker -- protein gene product (PGP) 9,5 -- revealed the presence of nerve fibers distributed in various regions of the knee joint synovial membrane. Confirming previous studies, some of these nerve fibers stained with antibodies to tyrosine hydroxylase (TH), neuropeptide Y (NPY), substance P (SP), calcitonin gene-related peptide (CGRP), and vasoactive intestinal polypeptide (VIP). In addition, dynorphin (DYN)-containing fibers were detected, which have not been reported previously in normal joints. In general, the immunoreactive fibers were observed close to the synoviocytes and at blood vessels. Fibers with colocalization of NPY- and TH-like immunoreactivities (LIs), as well as of DYN- and TH-LIs were demonstrated. In the electron microscope, bundles of unmyelinated fibers as well as single fibers were found in the connective tissue region below the synoviocytes. Varicose parts of the nerve fibers contained mainly small, clear vesicles. Small and large dense-cored vesicles were also seen, but less frequently. Denser portions of the plasma membranes of some axons were observed in these regions, facing the extracellular space. Myelinated fibers were also observed in some nerve bundles. These findings emphasize the complex innervation of the synovial membrane, with nerve fibers containing a host of neuroactive substances. Altogether, these fibers are probably involved in many functions such as vasoregulation and control of synovial secretion in addition to being a source of mediators in joint inflammation.

Ontogenetic changes in neuropeptide Y-like-immunoreactivity in the terminal nerve of the chum salmon and the cloudy dogfish, with special reference to colocalization with gonadotropin-releasing hormone-immunoreactivity

We observed ontogenetic changes of neuropeptide Y (NPY)-like-immunoreactivity in the terminal nerve (TN) of the chum salmon, a teleost, and the cloudy dogfish, an elasmobranch. In the chum salmon, NPY-like-immunoreactive (NPY-IR) cells first appeared in the olfactory placode of embryos at 16 days after fertilization, and then extended sequentially and centrally in the olfactory system. Colocalization of NPY- and gonadotropin-releasing hormone (GnRH)-like-immunoreactivities was also observed in TN ganglion cells. In the cloudy dogfish, NPY-IR cells first appeared in the rudimental TN ganglion of the embryo at the 40 mm stage. Then, the NPY-IR cells and fibers in the TN system increased in density during late embryonic periods. Colocalization of NPY- and GnRH-like-immunoreactivities in TN ganglion cells was not found in the developing or the adult dogfish.

Neuropeptide-Y innervation of the rat spleen: Another potential immunomodulatory neuropeptide

Neuropeptide-Y (NPY) is a 36 amino acid peptide that acts as a chemical messenger in the central and peripheral nervous systems. NPY often is found colocalized with the classical neurotransmitter norepinephrine (NE) and can potentiate the effects of this neurotransmitter postsynaptically in many systems. Using immunocytochemistry for NPY and specific lymphoid cell markers, we mapped the distribution of NPY-positive nerve fibers in the rat spleen. NPY-positive nerve fibers were present along the vasculature, trabeculae, and capsule, and also were found associated with specific lymphoid parenchymal compartments of the spleen, in close contact with lymphocytes and macrophages. These contacts were investigated further at the electron microscopic level. NPY-positive nerve terminals were found in close apposition with lymphocytes in the periarteriolar lymphatic sheath, and with lymphocytes and macrophages in the marginal zone. Previous studies have reported that postganglionic noradrenergic nerve fibers innervate specific lymphoid compartments of the rat spleen, with nerve terminals forming direct appositions with cells of the immune system. The possible colocalization of NPY and NE in these nerve fibers was investigated by chemical sympathectomy with 6-hydroxydopamine, followed by immunocytochemical labeling of NPY and tyrosine hydroxylase (TH), the rate-limiting enzyme in norepinephrine synthesis. Colocalization also was investigated by labeling for NPY with a fluorescent label, eluting the NPY, and staining for TH with diaminobenzidine as the label. These studies demonstrate that norepinephrine and NPY are colocalized in the postganglionic sympathetic nerve fibers of the rat spleen. Further studies are needed to determine whether lymphocytes and macrophages possess receptors for NPY, whether NPY fulfills the criteria for neurotransmission, and whether NPY plays a role in immunological phenomena either directly or by modulating norepinephrine.