BACKGROUND/AIMS: Neurotensin is a gut-brain peptide with both inhibitory and excitatory actions on the colonic musculature; our objective was to understand the implications of this for motor patterns occurring in the intact colon of the rat. METHODS: The effects of neurotensin with concentrations ranging from 0.1-100 nM were studied in the intact rat colon in vitro, by investigating spatio-temporal maps created from video recordings of colonic motility before and after neurotensin. RESULTS: Low concentration of neurotensin (0.1-1 nM) inhibited propagating long distance contractions and rhythmic propagating motor complexes; in its place a slow propagating rhythmic segmental motor pattern developed. The neurotensin receptor 1 antagonist SR-48692 prevented the development of the segmental motor pattern. Higher concentrations of neurotensin (10 nM and 100 nM) were capable of restoring long distance contraction activity and inhibiting the segmental activity. The slow propagating segmental contraction showed a rhythmic contraction—relaxation cycle at the slow wave frequency originating from the interstitial cells of Cajal associated with the myenteric plexus pacemaker. High concentrations given without prior additions of low concentrations did not evoke the segmental motor pattern. These actions occurred when neurotensin was given in the bath solution or intraluminally. The segmental motor pattern evoked by neurotensin was inhibited by the neural conduction blocker lidocaine. CONCLUSIONS: Neurotensin (0.1-1 nM) inhibits the dominant propulsive motor patterns of the colon and a distinct motor pattern of rhythmic slow propagating segmental contractions develops. This motor pattern has the hallmarks of haustral boundary contractions.
Absorption ; Animals ; Baths ; Colon* ; In Vitro Techniques ; Interstitial Cells of Cajal ; Lidocaine ; Myenteric Plexus ; Neural Conduction ; Neurotensin* ; Peristalsis ; Rats* ; Receptors, Neurotensin ; Video Recording

As a neuropeptide, neurotensin (NTS) is widely expressed in central and peripheral nervous system, which is mainly mediated byneurotensin receptor1 (NTSR1) to activate the related downstream signaling pathways. After summarized the function and mechanism of NTS/NTSR1 in various malignant tumors, we found that NTS/NTSR1 played essential roles during tumor initiation and development. NTS/NTSR1 regulates tumor initiation, proliferation, apoptosis, metastasis and differentiation mainly through three pathways, including IP3/Ca2+ /PKC/MAPKs pathway, MMPs/EGFR/MAPKs (PI3K/Akt) pathway, or Rho-GTPsaes and non-receptor tyrosine kinase pathway. Besides, NTS/NTSR1 is also regulated by some upstream pathways and some traditional Chinese medicine preparations and traditional Chinese medicine therapies. In this article, we summarized the function of NTS/NTSR1 and its mechanisms, and discussed the prospective in its application to clinical diagnosis and drugs targeting.
Animals ; Humans ; Medicine, Chinese Traditional ; Neoplasms ; etiology ; Neurotensin ; chemistry ; physiology ; Receptor, Epidermal Growth Factor ; physiology ; Receptors, Neurotensin ; chemistry ; physiology ; Signal Transduction ; physiology ; rhoA GTP-Binding Protein ; physiology

A complex set of brain based systems modulate feeding to maintain constant body weight. The adipose derived-hormone, leptin, plays a crucial role in this control by acting on diverse leptin receptor (LepRb)-expressing neurons in the hypothalamus and brainstem to modify behavior and metabolism. In addition to controlling energy expenditure and satiety, leptin controls motivation and the reward value of food by regulating two interconnected systems: hypocretin (HCRT) neurons and the mesolimbic dopamine (MLDA) system. Modest/acute decreases in leptin levels, as associated with mild caloric restriction, increase MLDA activity and overall food-seeking behavior; in contrast, severe starvation or complete leptin deficiency blunt MLDA activity, along with motivation and associated behaviors. Lateral hypothalamic (LHA) LepRb neurons project to dopamine (DA) neurons in the ventral tegmental area, where neurotensin (NT) release augments MLDA function; these LepRb(NT) cells also innervate HCRT neurons to control Hcrt expression and inhibit HCRT neurons. Ablation of LepRb in these cells abrogates the control of HCRT cells by leptin and decreases activity and MLDA function. We propose that this neural pathway regulates the MLDA, activity, and motivation in response to leptin and nutritional status.
Body Weight ; Brain ; Brain Stem ; Caloric Restriction ; Dopamine ; Energy Metabolism ; Hypothalamus ; Leptin ; Metabolism ; Motivation ; Neural Pathways ; Neurons ; Neurotensin ; Nutritional Status ; Obesity ; Orexins ; Receptors, Leptin ; Reward ; Starvation ; Ventral Tegmental Area

Neurotensin receptor-1 (NTR1), which can stimulate the intracellular cascade signal pathway, belongs to the large superfamily of G-protein coupled receptors. NTR1 is related to the occurrence and development of several kinds of diseases. In order to screen the inhibitors for the cancers associated with NTR1 protein, we established a CHO (Chinese hamster ovary) cell line in which human neurotensin receptor-1 was highly expressed. The method is to construct the recombinant plasmid which was lysed with the hNTR1 gene and transfect it into CHO cells. After selected with G418, the cell line was evaluated by Western blotting analysis and calcium flux assays. Through the calcium flux assays on FlexStation 3, we got the EC50 value of neurotensin peptide which is the natural NTR1 agonist, and the IC 50 value of SR48692 which is the known NTR1 antagonist. The established human CHO/NTR1 cell line can be used to study the profile of NTR1 biological activity and further screen of NTR1 antagonists and agonists.
Animals ; CHO Cells ; Calcium Signaling ; Cricetinae ; Cricetulus ; Humans ; Pyrazoles ; pharmacology ; Quinolines ; pharmacology ; Receptors, Neurotensin ; antagonists & inhibitors ; genetics ; metabolism ; Transfection

BACKGROUND/AIMS: Although neurotensin (NT) stimulates colon motility and the passage of intestinal contents, the associated mechanism of action remains unclear. The objective of this study was to investigate the effects of NT on colon motility using isolated rat colon. METHODS: Intraluminal pressure was measured at both the proximal and distal portions of the isolated colon. An isolated rat colon was perfused with Krebs solution via the superior mesenteric artery. After stabilization, NT was administered in concentrations of 14, 28, 138 and 276 pM. After pretreatment with phentolamine, propranolol, hexamethonium, atropine or tetrodotoxin, NT was administered at a concentration of 276 pM, and then the intraluminal pressure was monitored. RESULTS: NT significantly increased colon motility at concentrations of 14, 28, 138, and 276 in the proximal colon (25.1+/-6.5%, 175.4+/-117.0%, 240.8+/-115.1% and 252.3+/-110.6%, respectively) and in the distal colon (35.6+/-11.8%, 97.5+/-35.1%, 132.7+/-36.7% and 212.1+/-75.2%, respectively). The stimulant effect of NT was more potent in the proximal colon, in a concentration-dependent manner (P<0.05). The stimulant effect of NT was significantly inhibited by atropine at both the proximal and distal colon and by tetrodotoxin at the proximal colon, but not by tetrodotoxin at the distal colon and not by propranolol, phentolamine, or hexamethonium at both the proximal and distal colon. CONCLUSIONS: NT increased colon motility at both the proximal and distal portions of the rat colon. The effects were more prominent at the proximal portion. The results of this study suggest that the stimulant action of NT may be mediated by local cholinergic muscarinic receptors.
Animals ; Atropine ; Autonomic Pathways ; Colon ; Gastrointestinal Contents ; Hexamethonium ; Isotonic Solutions ; Mesenteric Artery, Superior ; Neurotensin ; Phentolamine ; Propranolol ; Rats ; Receptors, Muscarinic ; Tetrodotoxin

Animals ; Disease Models, Animal ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Female ; Heat Stress Disorders ; drug therapy ; metabolism ; Hypothalamus ; metabolism ; Male ; Neurotensin ; metabolism ; Phytotherapy ; Rats ; Rats, Wistar ; Tablets

OBJECTIVETo investigate the effect of plasma neuropeptide Y (NPY), neurotensin (NT) and their relationships on the diurnal rhythm of BP and target organ damage for essential hypertension.

METHODSAmbulatory BP monitoring (ABPM) for 24 hours was performed in ninety patients with essential hypertension and thirty healthy subjects. The patients were divided into two groups: 55 dippers and 35 non-dippers according to the ABPM results. Plasma NPY and NT levels in subjects were measured at 8:00, 16:00 and 2:00 o'clock by using radioimmunoassay method. Target organ functions were measured.

RESULTSThe plasma NPY level was higher and NT was lower in patients with hypertension those in normal controls (P < 0.001). Compared with dippers, non-dippers had a higher NPY and a lower NT plasma levels, especially appearing at 2:00 o'clock. The patients with left ventricular hypertrophy, stroke or kidney damage had a higher NPY and a lower NT levels compares with those without target organ damage.

CONCLUSIONThe changes in plasma NPY and NT may contribute to disturbance of the diurnal rhythm of blood pressure in patients with essential hypertension, especially in those with target organ damages, which may serve as a pathophysiologic mechanism for target organ damages in hypertension.

Adult ; Aged ; Blood Pressure ; Blood Pressure Monitoring, Ambulatory ; Circadian Rhythm ; Female ; Humans ; Hypertension ; blood ; physiopathology ; Male ; Middle Aged ; Neuropeptide Y ; blood ; Neurotensin ; blood

Animals ; Brain Injuries ; blood ; cerebrospinal fluid ; chemically induced ; Endotoxins ; toxicity ; Female ; Male ; Natriuretic Peptide, C-Type ; analysis ; Neurotensin ; analysis ; Rabbits

To study the tumor-suppression effect of a newly developed anti-tumor agent AG60 [ acriflavine (1) : guanosine (1) composition, Taerim Pharm. Co., Seoul, Korea], each Ehrlich carcinoma (107 cells)-inoculated mouse received the subcutaneous injection of 0.2 ml of saline, 5mg/kg of AG60, and 30 mg/kg of AG60, every other day for two weeks. Animals were sacrificed, and stomach, duodenum, appendix vermiformis and rectal tissues were resected and fixed in 10% neutral formalin. Tissue blocks were washed, dehydrated, embedded and cut in 6 microgram-thick sections. For immunocytochemistry, the streptavidine-biotin-peroxidse method was used with a InnoGenex (San Ramon, Calif., USA) staining kit. The tissues were incubated with rabbit antisera against somatostatin (Biogenesis, Poole, England, UK) diluted 1 : 300, secretin (Biogenesis, Poole, England, UK) diluted 1 : 2,400, neurotensin (Biogenesis, Poole, England, UK) diluted 1 : 2,600, or motilin (Biogenesis, Poole, England, UK) diluted 1 : 1,000 for 24 hour at 4dreeges C, followed by incubation in biotinylated antirabbit IgG and horseradish peroxidase-streptavidin conjugate for 1 hour at room temperature. The antigen-antibody reaction sites were visualized by incubating the sections with diaminobezidine tetrahydrochloride (DAB) for 5~15 minutes at room temperature. After mounting in canada balsam, they were examined in a Leica DM RB microscope. The number of the immunoreactive cells in the area of gastrointestinal mucosae (mean number of immunoreactive cells per 0.25mm2) were observed and calculated. The results are as follows : 1. In the fundic gland of normal mouse, somatostatin immunoreactive cells were detected (18.5+/-0.71), but neurotensin, secretin, or motilin immunoreactive cells were not found. In the duodenal mucosa of normal mouse, somatostatin immunoreactive cells were detected (7.0+/-0.10), but neurotensin, secretin or motilin immunoreactive cells were rarely found. 2. Immunoreactivity of somatostatin, secretin, neurotensin or motilin cells was not found in appendix vermiformis and rectum of normal mouse. 3. On immunocytochemical study, somatostatin immunoreactive cells in the fundic glands of normal, experimental control, AG60 (5mg/kg)-treated, AG60 (30 mg/kg)-treated and 5-fluorouracil (60 mg/kg)-treated groups were 18.5+/-0.71, 10.0+/-4.20, 11.5+/-0.71, 13.5+/-2.10, 11.5+/-2.71, respectively. 4. On immunocytochemical study, somatostatin immunoreactive cells in the duodenal mucosae of normal, experimental control, AG60 (5 mg/kg)-treated, AG60 (30 mg/kg)-treated and 5-fluorouracil (60 mg/kg)-treated groups were 7.0+/-2.10, 0.5+/-2.71, 3.0+/-1.41, 0.5+/-0.71, 2.50+/-0.71, respectively. 5. On immunocytochemical study, secretin immunoreactive cells in the duodenal mucosae of normal, experimental control, AG60 (5 mg/kg)-treated, AG60 (30 mg/kg)-treated and 5-fluorouracil (60 mg/kg)-treated groups were rarely found. 6. On immunocytochemical study, neurotensin and motilin immunoreactive cells in the duodenal mucosae of normal groups were detected, but immunoreactivies were not detected in experimental control, AG60 (5 mg/kg)-treated, AG60 (30 mg/kg)-treated or 5-fluorouracil (60 mg/kg)-treated groups.
Acriflavine ; Animals ; Antigen-Antibody Reactions ; Appendix ; Armoracia ; Canada ; Duodenum ; England ; Enteroendocrine Cells* ; Fluorouracil ; Formaldehyde ; Guanosine ; Immune Sera ; Immunoglobulin G ; Immunohistochemistry ; Injections, Subcutaneous ; Mice* ; Motilin ; Mucous Membrane ; Neurotensin ; Rectum ; Secretin ; Seoul ; Somatostatin ; Stomach

We have cloned the mouse neurotensin/neuromedin N (NT/N) gene from the murine mast cell line C1.MC/C57.1 for the first time. The murine NT/N cDNA clone consisted of 765 nucleotides and coded for 169 peptide residues with an N-terminal signal peptide, and the C-terminal region contained of one copy of neurotensin (NT) and one copy of neuromedin N (NN). Total of four Lys-Arg dibasic motifs were present; one each at the middle of the open reading frame, at the N-terminal of NN, at the C-terminal of NT, and between NN and NT. Amino acid sequence analysis of the mouse NT/N revealed 90% homology to that of the rat NT/N gene. NT/N is expressed in routine mast cell lines (C1.MC/C57.1 and P815), but not in murine bone marrow-derived mast cells (BMMCs), murine macrophage cell line (RAW 264.7), nor in murine T cell line (EL-4). NT/N mRNA in C1.MC/C57.1 is highly inducible by IgE cross-linking, phorbol myristate acetate, neurotensin, and substance P. Following the treatment of demethylating agent, 5-azacytidine (5-azaC), the NT/N gene was induced in BMMCs in response to IgE cross-linking. 5-azaC-treated BMMCs did not express the NT/N gene without additional stimuli. These findings suggested that the regulation of NT/N gene expression was dependent on the effects of not only gene methylation but also enhancer and/or repressor proteins acting on the NT/N promoter.
Animals ; Azacitidine ; Cell Line ; Clone Cells ; DNA, Complementary ; Gene Expression ; Immunoglobulin E ; Macrophages ; Mast Cells* ; Methylation ; Mice ; Neurotensin ; Nucleotides ; Open Reading Frames ; Protein Sorting Signals ; Rats ; Repressor Proteins ; RNA, Messenger ; Sequence Analysis, Protein ; Substance P ; Tetradecanoylphorbol Acetate