Neuropeptide Tyrosine Immunoreactivity Research Articles

Organization of neuropeptide tyrosine-like immunoreactive system in the brain of the Antarctic fish, Trematomus bernacchii

Antarctic notothenioids have developed unique freezing-resistance adaptations, including brain diversification, to survive in the subzero waters of the Southern Ocean surrounding Antarctica. In this study we have investigated the anatomical distribution of neuropeptide tyrosine (NPY)-like immunoreactive elements in the brain of the Antarctic fish Trematomus bernacchii, by using an antiserum raised against porcine NPY. Perikarya exhibiting NPY-like immunoreactivity were observed in distinct regions of the brain. The most rostral group of immunoreactive perikarya was found in the telencephalon, within the entopeduncular nucleus. In the diencephalon, three groups of NPY-like immunoreactive perikarya were found in the hypothalamus. Two groups of positive cell bodies were found in distinct populations of the preoptic nucleus, whereas the other group was found in the nucleus of the lateral recess. More caudally, NPY immunoreactivity was detected in large neurons located in the subependymal layers of the dorsal tegmentum of the mesencephalon, medially to the torus semicircularis. NPY-like immunoreactive nerve fibres were more widely distributed throughout the telencephalon to the rhombencephalon. High densities of nerve fibres and terminals were observed in several regions of the telencephalon, olfactory bulbs, hypothalamus, tectum of the mesencephalon and in the ventral tegmentum of the rhombencephalon. The distribution of NPY-like immunoreactive structures suggests that, in Trematomus, this peptide may be involved in the control of several brain functions, including olfactory activity, feeding behaviour, and somatosensory and visual information. In comparison with other neuropeptides previously described in the brain of Antarctic fish, NPY is more widely distributed. Our data also indicate the existence of differences in the brain distribution of NPY between Trematomus and other teleosts. In contrast with previous results reported in other fish, Trematomus contains positive fibres in the olfactory bulbs and immunoreactive perikarya in the nucleus of the lateral recess, whereas NPY-immunopositive cell bodies are absent in the thalamus and rhombencephalon, and no NPY immunoreactivity is present in the pituitary. These differences could be related to the Antarctic ecological diversity of notothenioids living at subzero temperatures.

Neurochemical and cellular markers in human cervix of late pregnant, postpartal and non-pregnant women

The aim was to evaluate the peptidergic innervation and the dendritic cell content in the cervix uteri. Cervical biopsies were obtained from late pregnant (n=5), postpartal (n=5) and non-pregnant (n=5) women. The samples were prepared for immunohistochemistry using antibodies to protein S-100 (S-100), calcitonin gene-related peptide (CGRP), vasoactive intestinal polypeptide (VIP), human peptide histidine isoleucine amide (PHM 27), neuropeptide tyrosine (NPY), and human histocompatibility complex class II subregion DR (HLA-DR). Nerve fibers positive for protein S-100, and dendritic cells positive for S-100 and HLA-DR were abundant in the cervix, especially at late pregnancy. CGRP, VIP, PHM-27 and NPY positive nerve fibers were present in non-pregnant, short nerve fibers and scattered immunoreactivity at term, and further scattered immunoreactivity after parturition. NPY positive nerve fibers were decreased at term, and after parturition a scattered immunoreactivity was observed. The abundant protein S-100 positive nerve fibers implies an impact of myelinated nerves in the cervix uteri during pregnancy. The abundant dendritic cells, positive for HLA-DR and S-100, especially at term, indicates a general activation of the immune system until late pregnancy and parturition. The changed occurrence and distribution of immunoreactivity for CGRP, VIP and PHM-27 suggest a release of these neuropeptides until term. The changes in NPY immunoreactivity indicate a release of NPY around parturition.

Identification of the Pancreatic Endocrine Cells of Pseudemys scripta elegans by Immunogold Labeling

The endocrine pancreatic cells of Pseudemys scripta elegans were investigated immunocytochemically by light and electron microscopy. Insulin-, somatostatin (SST)-1, SST-28 (1-12)-, salmon (s)SST-25-, glucagon-, pancreatic polypeptide (PP)-, peptide tyrosine tyrosine (PYY)-, and neuropeptide tyrosine (NPY)-like immunoreactivities were observed. Insulin cells were immunogold labeled with bonito insulin antiserum and secretory granules were characterized by a wide halo and a dense core of varying shape. Consecutive PAP-immunostained sections showed that SST-28 (1–12), SST-14, and sSST-25 immunoreactivities occurred in the same cells. However, preabsorption tests demonstrated that anti-sSST-25 serum detected the invariant SST-14 molecule. The SST-28 (1–12)/SST-14-immunogold-labeled cells mainly had round or ovoid medium electron-dense granules. Glucagon-IR cells were characterized by round secretory granules with an electron-dense core, with or without a narrow clear halo. There were PP, PYY, and NPY (NPY-like) immunoreactivities in a population of glucagon-IR cells in the pancreatic duodenal region (glucagon/NPY cells). Most of the secretory granules of these glucagon/NPY-like cells had an electron-dense content and were round, although there were also pyriform or ovoid secretory granules which were smaller than those of glucagon-IR cells. Preabsorption tests proved that the NPY-like peptides detected in the endocrine pancreas of P. scripta elegans were more similar to NPY or PYY than to PP.

Localization of biogenic amines and neuropeptides in adrenal medullary cells of birds.

The present article reviews the immunohistochemical findings on the localization of biogenic amines and neuropeptides in adrenal medullary cells of birds. In the chicken, about 70% of medullary cells are adrenaline-containing cells and the rest of cells seem to be noradrenaline-containing cells. The ratio of adrenaline-cells to noradrenaline-cells extremely varies among avian species. Besides adrenaline and noradrenaline, medullary cells of birds contain many kinds of biogenic amines and neuropeptides: serotonin, galanin, cholecystokinin, somatostatin, enkephalin, neuropeptide tyrosine and atrial natriuretic peptide. The existence of these bioactive substances in medullary cells also exhibits interspecies heterogeneity. In the chicken, serotonin and galanin are contained in both adrenaline- and noradrenaline-cells of the adrenal gland. Cholecystokinin- and somatostatin-immunoreactivity is restricted to adrenaline-containing cells. Enkephalin-immunoreactivity is seen in both adrenaline- and noradrenaline-cells, but in about half of medullary cells. Neuropeptide tyrosine-immunoreactivity is found in the adrenal gland of the chick embryo and newly hatched chick, but not in the adult chicken. Serotonin and these neuropeptides may be selectively coreleased with adrenaline and/or noradrenaline from adrenal medullary cells of the chicken.

An immunocytochemical study of cutaneous innervation and the distribution of neuropeptides and protein gene product 9.5 in man and commonly employed laboratory animals

The cutaneous nerves of rat, cat, guinea pig, pig, and man were studied by immunocytochemistry to compare the staining potency of general neural markers and to investigate the density of nerves containing peptides. Antiserum to protein gene product 9.5 (PGP 9.5) stained more nerves than antisera to neurofilaments, neuron-specific enolase (NSE), and synaptophysin or histochemistry for acetylcholinesterase (AChE). Peptidergic axons showed species variation in density of distribution and were most abundant in pig and fewest in man. However, the specific peptides in nerves innervating the various structures were consistent between species. Nerve fibers immunoreactive for calcitonin gene-related peptide (CGRP) and/or vasoactive intestinal polypeptide (VIP) predominated in all the species; those immunoreactive to tachykinins (substance P and neurokinin A [NKA]) and neuropeptide tyrosine (NPY) were less abundant. Neonatal capsaicin, at the doses employed in this study, destroyed approximately 70% of CGRP- and tachykinin-immunoreactive sensory axons; whereas 6-hydroxydopamine (6-OHDA) at the doses employed resulted in a complete loss of NPY and tyrosine hydroxylase (TH) immunoreactivity without affecting VIP, CGRP, and tachykinins. Thus, this study confirms that antiserum to PGP 9.5 is the most suitable and practical marker for the demonstration of cutaneous nerves. Species differences exist in the density of peptidergic innervation, but apparently not for specific peptides. Not all sensory axons immunoreactive for CGRP and substance P/NKA are capsaicin-sensitive. However, all sympathetic TH- and NPY-immunoreactive axons are totally responsive to 6-OHDA; but no change was seen in VIP-immunoreactive axons, suggesting some demarcation of cutaneous adrenergic and cholinergic sympathetic fibers.

Quantitation of tyrosine hydroxylase and neuropeptide Y immunoreactivity in single rat sympathetic neurons: Effects of preganglionic nerve activity

Using computerised densitometry to measure immunocytochemical reaction product in a model system, we established conditions that produced a linear relationship between the logarithm of antigen concentration and the measured intensity of staining. We then applied the densitometric technique to assess the changes in tyrosine hydroxylase (TH) and neuropeptide tyrosine (NPY) within sympathetic neurons of rat superior cervical ganglion following chronic decentralization and following reserpine treatment. One week after surgical or pharmacological decentralization, there was appreciable reduction of neuronal levels of both TH and NPY. However, there remained considerable variation in the immunoreactivities of individual cells. Three days of treatment with reserpine elevated TH levels but substantially reduced NPY. Both these effects were prevented by prior decentralization of the ganglia. No differences were seen between normotensive and the Otago strain of genetically hypertensive rats, either in basal TH or NPY immunoreactivities or in responses to the maneuvers performed. Comparison of our findings with previous biochemical data indicate that densitometric immunocytochemistry provides an accurate index of neuronally localised antigen concentrations but also allows analysis of interneuronal differences that are not otherwise apparent.

Co-localization of neuropeptide tyrosine (NPY) and its C-terminal flanking peptide (C-PON)

Neuropeptide tyrosine (NPY) is one of the most abundant and widespread peptides in the mammalian nervous system. Recent isolation and sequencing of the DNA encoding NPY has predicted the existence of a 97 amino acid precursor peptide. Proteolytic processing of this precursor could yield three separate peptide products, an N-terminal signal peptide, neuropeptide tyrosine and a 30 amino acid C-terminal flanking peptide (C-PON). Here, we present evidence that the predicted C-flanking peptide of NPY is widely distributed in both the central and peripheral nervous systems of several mammalian species including man, and has an identical distribution to NPY. It was also demonstrated, using correlative light microscopic immunostaining on serial sections and double electron microscopic immunocytochemistry, that C-PON and NPY immunoreactivities are co-localized in neuronal cell bodies of the brain cortex, sympathetic ganglion cells, norepinephrine-containing granules of the adrenal medulla and in human pheochromocytoma tumor cells.

Neuropeptide tyrosine (NPY): a newly discovered peptide is present in the mammalian respiratory tract.

Neuropeptide tyrosine (NPY), a newly discovered peptide known to modulate blood vessel diameter and smooth muscle tone, has been found in many mammalian organs. Its distribution is similar to that of sympathetic nerve fibres and NPY immunoreactivity has been found in noradrenergic ganglion cells. In a study of the respiratory tract of four mammalian species--man, cat, guinea pig, and rat--NPY immunoreactivity has been localised to nerve fibres. NPY immunoreactive nerve fibres were found in the adventitia of blood vessels and in the airway smooth muscle. Its distribution was strikingly similar to that of sympathetic nerve fibres as demonstrated by dopamine-beta-hydroxylase antibodies. The mean (SD) concentrations of NPY in the guinea pig respiratory tract, as determined by radioimmunoassay of tissue extracts, were: upper trachea 3.3 (0.7), lower trachea 2.0 (0.5), and major bronchus 3.5 (1.1) pmol/g. During developmental studies in man NPY immunoreactive nerve fibres were first observed at 20 weeks' gestation in the trachea, and fibres gradually extended down into the intrapulmonary airways after birth. NPY immunoreactive nerve fibres have a distribution and developmental pattern similar to that of sympathetic nerve fibres in the respiratory tract. The finding of NPY immunoreactivity in nerve fibres in the mammalian respiratory tract adds to the growing number of peptides having potent biological actions found in this organ, and shows that the lung possesses a rich peptidergic system, which may influence pulmonary function.

NEUROPEPTIDE TYROSINE (NPY) IMMUNOREACTIVITY IN NOREPINEPHRINE-CONTAINING CELLS AND NERVES OF THE MAMMALIAN ADRENAL GLAND

The application of immunocytochemistry at both light and electron microscopic levels has revealed neuropeptide tyrosine (NPY)-immunoreactive material to be localized to norepinephrine-containing endocrine cells in the adrenal medulla and also to varicose nerve fibers penetrating the adrenal cortex of several mammalian species, including horse, cat, rat, guinea pig and mouse. Correlative electron microscopic immunostaining has revealed that enkephalin and NPY immunoreactivities are co-localized to the same norepinephrine-containing secretory granules. High concentrations of NPY have been extracted from the mouse adrenal gland (1243.7 +/- 122.8 pmol NPY/g wet tissue; mean +/- SE). Chromatographic analysis has shown the extracted material to correspond with pure natural NPY.