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Secretoneurin (SN) is a neuropeptide formed by endoproteolytic processing of secretogranin II (chromogranin C). Chromatographic analysis revealed that the human retina contains significant concentrations (14.2 fmol/mg wet weight) of this peptide. Its cellular localization in the retina was characterized by immunohistochemistry. SN-immunoreactive (IR) fibers showed a distinct distribution in central...
Neurons of the guinea pig IMG are surrounded by nerve fibers containing CGRP-like immunoreactivity (LI). The purpose of this study was to determine whether colonic distension releases CGRP-LI in the IMG and whether opioid peptides and neurotensin(8-13) [NT(8-13)] modulate its release. Colonic distension released CGRP-LI. Methionine-enkephalin acted through mu and/or delta receptors to block release...
In sheep, arginine vasopressin (AVP) and corticotropin-releasing factor (CRF) stimulate adrenocorticotropic hormone (ACTH) secretion. Increased hypothalamic secretion of these peptides at the end of gestation initiates parturition in this species. We hypothesized that CRF and/or AVP content in the fetal hypothalamus increases late in gestation and that this content was comprised of multiple molecular...
We examined the binding characteristics of the two endogenous forms of C-type natriuretic peptide (CNP-22 and CNP-53) and their effects on cyclic GMP (cGMP) accumulation in primary cultures of mouse astrocytes. CNP-22 and CNP-53 competitively inhibited the specific binding of [ 125 I][Tyr 0 ]CNP, with an IC 50 value of 32 and 37 pM, respectively. They also induced...
The biosynthesis of neuropeptide Y (NPY) was investigated to determine the efficiency of synthesis and processing of the precursor. In brain tissues examined, the major product was amidated NPY(1-36). Although this was also the major product in adrenal and heart atrium, a minor portion of the immunoreactivity was identified as unprocessed precursor. NPY degradation was investigated using SK-N-MC...
Immunohistochemical methods allowed us to study the distribution of neurotensin immunoreactivity (NT-IR) in the infundibular area of the guinea pig and to obtain evidence of a clear increase of such immunoreactivity in females during lactation. By use of the double immunolabeling method we demonstrated the presence of NT in the tuberoinfundibular dopaminergic (TIDA) neuronal system, in the nerve...
In this report we describe the development of a radioimmunoassay for neuropeptide K (NPK) that is not influenced by the presence of free neurokinin A (NKA) or neuropeptide γ (NPG). The antisera for the radioimmunoassay were obtained by immunizing rabbits with β-preprotachykinin A fragment 69-91. This fragment contains the sequence 1-20 of NPK and has only the sequence 18-20 (Gly-His-Gly) in common...
We studied the effect of the prostaglandin synthesis inhibitor, indomethacin, on pentagastrin-associated enhancements of gastric mucosal defense mechanisms, using a microfluorometric technique in which mucus gel thickness, intracellular pH (pH i ), gastric mucosal blood flow, and acid secretion were measured simultaneously in vivo. Intravenous infusion with pentagastrin (80 μg/kg/h) increased...
Oryzatensin (Gly-Tyr-Pro-Met-Tyr-Pro-Leu-Pro-Arg) is an ileum-contracting and immunostimulating peptide derived from rice albumin. The mechanisms for the ileal contraction that it induces, consisting of rapid and slow components, were examined. The rapid contraction was mediated by histamine release and the slow contraction by a prostaglandin E 2 -like substance, judging from the effects...
To investigate the role of the hormone vasopressin (VP) in mediating the response of an organism to food restriction stress-induced analgesia, tail flick latencies and scored qualitative behavioral responses were recorded in VP-containing (LE) rats and VP-deficient (DI) rats. These variables were measured under nonstressed (ad lib) and stressed (food restriction) conditions. In the ad lib condition,...
The purpose of present study was to determine whether peptidase activity affects the release of substance P (SP) and calcitonin gene-related peptide (CGRP) from spinal cord slices. When slices were exposed to various inhibitors of endopeptidase 24.11, the resting and capsaicin-stimulated release of SP were less than 0.04% and 0.20% total content per minute, respectively. Resting CGRP release was...
Regulation of prohormone convertase expression was studied in two neuropeptide-producing cell lines, the human neuroepithelioma cell line SK-N-MCIXC and the rat medullary thyroid carcinoma cell line WE 4/2. The cells were treated with the phosphodiesterase inhibitor isobutyl-methylxanthine and the tumor-promoting phorbol ester, phorbol-12-myristate-13 acetate, activators of the cyclic AMP (cAMP)...
The behavioral effects of α-MSH, MCH, and α-MSH + MCH were investigated in the ventromedial nucleus (VMN) and medial preoptic area (MPOA) (bilateral, 100 ng in 0.5 μl). Infusion of α-MSH into the VMN increased aggressive behavior; in the MPOA it reduced exploration and increased anxiety. In both areas it stimulated sexual behavior. MCH also stimulated sexual behavior in the MPOA and VMN and had...
Bombesin (BN) suppresses food intake more than an equimolar dose of neuromedin B-10 (NMB-10) or gastrin-releasing peptide(1-27) [GRP(1-27)]. Because BN is active at both NMB- and GRP-proferring receptors, it is possible that its greater potency is due to the simultaneous activation of both receptor subtypes. This hypothesis was tested by administering a mixture of NMB-10 and GRP(1-27). The results...
Neuropeptides were characterized in two similar identified neurons termed pedal 5 and 6 (Pd5 and Pd6). Both neurons appear white, a characteristic of peptidergic neurons, and send peripheral axons down several nerves that innervate the foot and control locomotion. Gel electrophoresis of neurons incubated with labeled amino acids indicated that individually dissected Pd5 and Pd6 neurons synthesized...
The present study assessed the direct immunomodulatory effect of a panel of synthetic peptides exhibiting δ-opioid receptor agonist activity. Murine splenic lymphocytes and peritoneal macrophages were cultured in vitro with peptides at concentrations of 0.00001-10 μM. Assessment was made of B-cell function by quantitating cellular proliferation, T-cell function by measuring cytokine production,...
Exogenous substance P (10-80 nmol/ml) induced a dose-dependent increase in nasal symptoms in asymptomatic allergics with rhinitis (n = 15) and controls (n = 8), but did not release any mediators. However, comparing the antigen-evoked release of mediators into nasal secretions with that of a substance P-pretreated antigen challenge, we found a significant enhancement of kinins, TAME esterase activity...
The present study has measured EGF levels in primary brain tumor tissues. EGF levels were measured by specific radioimmunoassay (RIA) and further analyzed by reversed-phase high performance liquid chromatography (RP-HPLC) followed by RIA and radioreceptor binding. The levels of EGF-like immunoreactivity (EGF-LI) in astrocytoma-IV tumors were fourfold greater than those in normal brain tissues. In...
Endopeptidase 24.11 (EP 24.11), a membrane-bound cell surface enzyme, modulates chemotactic responsiveness of neutrophils to f-Met-Leu-Phe. It is unknown if the enzyme degrades potent formylmethionyl tetrapeptides or if an enzyme with similar activities, endopeptidase 24.15 (EP 24.15), degrades formylated chemotactic peptides. In a study of five formylmethionyl tetrapeptides and f-Met-Leu-Phe, we...
The role of trout substance P (tSP) and neurokinin A (tNKA) in cardiovascular regulation was investigated in the rainbow trout, Oncorhynchus mykiss, in vivo and in vitro. In vivo, the coeliac arterial and ventral aortic relative blood flows were measured with Doppler flow probes, and blood pressure was measured via a cannula inserted into the dorsal aorta. tSP (0.1 and 1 nmol kg -1 ...
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