This study was to observe the effect and possible mechanism of somatostatin analogue octreotide (OCT) on cross excitation of adjacent segment of spinal nerve in rat. Cutaneous branches of T9-T13 spinal dorsal rami were chosen and dissected free for the following recording and stimulation. Only single unit fiber was used for recording, and the adjacent segment of nerve stem was used for antidromic electrical stimulation. To investigate the change of discharge rate and mechanical threshold, OCT and (or) somatostatin receptor antagonist cyclo-somatostatin (c-SOM) were applied to the receptive field following the antidromic electrical stimulation. The result showed that injection of OCT inhibited the increase of discharge rate and the decrease of mechanical threshold induced by the electrical stimulation (cross excitation); c-SOM reversed the effects of OCT. Application of c-SOM alone enhanced the cross excitation effects. The results suggest local application of somatostatin analogue OCT can inhibit the cross excitation between the two segments of spinal nerve by somatostatin receptor.
Animals ; Electric Stimulation ; Octreotide ; pharmacology ; Peptides, Cyclic ; pharmacology ; Rats ; Receptors, Somatostatin ; physiology ; Somatostatin ; analogs & derivatives ; Spinal Nerves ; drug effects

AIMTo know the effect of cysteamine (CS) on the plasma levels of somatostatin (SS) and some metabolic hormones in adult geese.

METHODSFourteen adult crossbred geese (Chuan white x Tai lake) fitted with chronic wing vein cannulas were used in this study to evaluate the effect of CS on SS, TSH, T3 and T4 levels. The experiment was consisted of control and treated phase. The diet was added CS at dosage of 100 mg/kg bw on the first day of the treated phase. The blood samples were collected from the cannulas and analyzed by radioimmunoassay.

RESULTSThe plasma SS concentration was (1.87 +/- 0.10) microg/L in control phase. Whereas SS concentrations on day 1, 3, 5, 7 of treated phase were decreased markedly (P < 0.05 or P < 0.01). Thereafter it was rose on the seventh day, however it was still lower than that of control. The thyroid stimulating hormone (TSH) content (2.45 +/- 0.31 mIU/L) was significantly decreased by 21.63% (P < 0.01) on day 1, and 18.37% (P > 0.05) on day 3 and day 5. Comparing with control phase (5.41 +/- 0.98 microg/L), T4 contents were elevated by 60.26% (P < 0.01), 43.25% (P < 0.01), 37.15% (P < 0.01) and 16. 82% (P < 0.01) respectively on day 1, 3, 5, 7. T3 level was (1.05 +/- 0.06) microg/L in control phase, whereas the levels was significantly increased by 36.19% (P < 0.01) on day 3. Also, the insulin concentration was higher than that of control (4.43 +/- 0.41 mU/ L) by 18.28% (P < 0.05) on the day 5.

CONCLUSIONThese results indicate that CS can decrease the plasma SS and TSH levels, whereas increase the levels of T4, T3 and insulin, therefore change metabolism, improve the nutrition transform and accelerate the growth in geese.

Animals ; Cysteamine ; pharmacology ; Diet ; Geese ; Insulin ; blood ; Somatostatin ; blood ; Thyrotropin ; blood ; Thyroxine ; blood ; Triiodothyronine ; blood

To determine whether exocrine pancreatic secretion is regulated by endogenous somatostatin, somatostatin deficiency was induced by cysteamine. Rats were subcutaneously administered a single dose of cysteamine (30 mg/100 g body weight) 12 hr before experiment. Anesthetized rats were prepared with cannulation into bile duct, pancreatic duct, duodenum, and jugular vein and pancreatic juice was collected. For in vitro study, isolated pancreata of rats, pretreated with cysteamine, were perfused with an intraarterial infusion of Krebs-Henseleit solution (37 degrees C) at 1.2 mL/min, and pancreatic juice was collected in 15-min samples. In vivo experiment of the rat, the mean basal pancreatic secretions, including volume, bicarbonate, and protein output were significantly increased from 18.4+/-0.5 microL/30 min, 0.58+/-0.05 microEq/30 min, and 214.0+/-26.1 microg/30 min to 51.6+/-3.7 microL/30 min, 1.52+/-0.11 microEq/30 min, and 569.8+/-128.9 microg/30 min, respectively (p<0.05). In the isolated perfused pancreas, cysteamine also resulted in a significant increase in basal pancreatic secretion (p<0.05). Simultaneous intraarterial infusion of octreotide (10 pmol/hr) to isolated pancreata partially reversed the effect of cysteamine on basal pancreatic secretion. These findings suggest that endogenous somatostatin play an important role on the regulation of basal pancreatic exocrine secretion.
Animal ; Cysteamine/pharmacology* ; Hormone Antagonists/pharmacology* ; Hormones, Synthetic/pharmacology ; In Vitro ; Male ; Octreotide/pharmacology ; Pancreas/secretion ; Pancreas/drug effects* ; Perfusion ; Rats ; Rats, Sprague-Dawley ; Somatostatin/antagonists & inhibitors*

OBJECTIVETo study regulative action of mica monomer granule preparation on gastrin (GAS), somatostatin (SS) and G cells as well as D cells of gastric mucosa in experimental chronic atrophic gastritis (CAG) rat.

METHODCAG rats were treated with mica monomer granule preparation with three different dosages--high, moderate and low level respectively. Changes of blood serum GAS, blood plasma SS and G cells as well as D cells of gastric mucosa in CAG rats were observed and detected with ELISA method, RIA method and immunocytochemistry method.

RESULTMica monomer granule of three different dosages could increase the quantity of G cells as well as D cells of gastric mucosa and the concentration of blood serum GAS and decrease the content of blood plasma SS in CAG rat at different level respectively. It was more effective in high and moderate dosage groups.

CONCLUSIONMica has the pharmacological action of protecting gastric mucosa, promoting the palingenesis of gastric gland and enhancing blood stream of gastric mucosa consequently to abate the inflammation reaction of gastric mucosa. Its effective mechanism is associated with the neuroendocrine regulative mechanism of promoting the secretion of gastric acid and gastric pepsin by increasing the amount of G cells as well as D cells and the concentration of blood serum GAS, and reducing inhibiting action on GAS secretion and enhancing the secretion of GAS by decreasing the content of SS.

Aluminum Silicates ; administration & dosage ; pharmacology ; Animals ; Dose-Response Relationship, Drug ; Gastric Mucosa ; pathology ; Gastrin-Secreting Cells ; drug effects ; Gastrins ; blood ; Gastritis, Atrophic ; blood ; pathology ; Materia Medica ; administration & dosage ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Somatostatin ; blood ; Somatostatin-Secreting Cells ; drug effects

Amino Acid Sequence ; Animals ; Antineoplastic Agents ; chemistry ; metabolism ; pharmacology ; Apoptosis ; drug effects ; Humans ; Molecular Structure ; Neoplasms ; pathology ; prevention & control ; Receptors, Somatostatin ; metabolism ; Somatostatin ; chemistry ; metabolism ; pharmacology ; Structure-Activity Relationship

OBJECTIVES: Investigate the influence of benazepril and amlodipine on the expression of secretin (PZ) and somatostatin (SS) in spontaneously hypertensive rats (SHR). METHODS: Forty-five SHRs (14 weeks old, male) were randomly assigned into 3 groups (=15):SHR group, Benazepril group (which was given benazepril 0.90 mg·kg·d) and Amlodipine group (SHRs were given amlodipine 0.45 mg· kg·d), taking WistarKyoto(WKY) as normal control (=15), meanwhile, rats in SHR group and WKY group were given the same volume of distilled water. After 8 weeks of intervention, the expression of protein and mRNA of PZ in duodenum and SS in sinuses ventriculi was detected by enzyme-linked immunoassay and RT-PCR. RESULTS: After 8 weeks of intervention, compared with the WKY group, the expression of protein and mRNA of PZ in duodenum and SS in sinuses ventriculi was increased significantly in SHR group (<0. 05). Compared with SHR group, the expression of PZ in duodenum and SS in sinuses ventriculi was decreased significantly in Benazepril group and Amlodipine group (<0.05). Compared with Benazepril group, in Amlodipine group the expression of PZ mRNA in duodenum and SS mRNA in sinuses ventriculi was decreased more significantly (<0.05). CONCLUSIONS The regulation disorder of PZ in duodenum and SS in sinuses ventriculi exists in SHR. The antihypertensive effect of benazepril and amlodipine may be realized by regulating the expression of PZ and SS, while the regulation of amlodipine is more obvious than benazepril.
Amlodipine ; pharmacology ; Animals ; Antihypertensive Agents ; pharmacology ; Benzazepines ; pharmacology ; Blood Pressure ; Hypertension ; drug therapy ; Male ; Random Allocation ; Rats ; Rats, Inbred SHR ; Rats, Inbred WKY ; Secretin ; metabolism ; Somatostatin ; metabolism

In this study of the inhibitory effects of angiopeptin and aspirin on the development of accelerated graft atherosclerosis (AGAS), 22 B10.BR mice received intra-abdominal heterotopic heart transplants from B10.A mice, without immunosuppression. Group 1 (n = 5) received no pharmacological intervention, Group 2 (n = 6) was treated with angiopeptin, Group 3 (n = 5) with aspirin, and Group 4 (n = 6) with both. There was no significant difference in the incidence of AGAS among these groups. The magnitude of intimal lesion development showed less narrowing of large vessels (> 100 microns in diameter) in groups 2 and 4--i.e. the groups received angiopeptin (Group 1 = 46.9 +/- 9.3%, Group 2 = 28.5 +/- 9.2%, Group 3 = 44.1 +/- 10.9%, Group 4 = 24.2 +/- 5.9%; p < 0.01). Comparison of the fraction of tropomyosin-positive staining cells in the intima revealed a lesser degree of staining in Group 2 (p < 0.01). No intervention was effective in preventing smooth muscle cell proliferation in the media or inflammatory cell infiltration in the adventitia. In conclusion, our data suggest that angiopeptin is effective in the direct inhibition of intimal smooth muscle cell proliferation in relatively large vessels, whereas aspirin exhibits no inhibitory role in the progression of AGAS. Angiopeptin appears to be a potential therapeutic agent for inhibiting the progression of postoperative AGAS in clinical heart transplantation.
Animal ; Aspirin/pharmacology* ; Cardiovascular Agents/pharmacology* ; Coronary Arteriosclerosis/pathology ; Coronary Arteriosclerosis/immunology* ; Coronary Vessels/pathology ; Coronary Vessels/drug effects ; Heart/drug effects* ; Heart Transplantation/immunology* ; Immunohistochemistry ; Mice ; Mice, Inbred Strains ; Myocardium/pathology ; Myocardium/immunology ; Oligopeptides/pharmacology* ; Somatostatin/pharmacology ; Somatostatin/analogs & derivatives* ; Transplantation, Homologous/immunology ; Tropomyosin/metabolism

OBJECTIVETo determine the effects of ginsenosides Rb1(GSRb1) on learning and memory and expression of somatostatin (SS) in the hippocampus and the frontal cortex in rat model of sleep deprivation (SD).

METHODSRats were randomized into groups of SD 2 d, SD 4 d, SD 6 d, and SD 0 d, while each group was sub-divided into GSRb1 group and normal saline (NS) sub-groups. Rats were intraperitoneal administered with 30 mg/(kg*d) of GSRb1 or NS for 7 d, then the learning and memory abilities were examined by measuring average swimming speed and mean escape latency using Morris maze.Expression of somatostatin was detected with immunohistochemical method and image analysis in the hippocampus and the frontal cortex.

RESULTSCompared with SD 0 d rats, SD rats exhibited significant decrease in the average swimming speed and increase in the escape latency (P <0.01). The expression of somatostatin in the hippocampus was decreased significantly in SD 2 d, SD 4 d and SD 6 d rats (P<0.05). However, decrease was only observed in SD 4 d and SD 6 d rats in the frontal cortex (P <0.05). Parallel comparison between NS control and GSRb1 treated rats demonstrated that rats treated with GSRb1 in each subgroup exhibited faster swimming speed and shorter escape latency (P <0.05). Meanwhile, the expression of somatostatin was increased in SD 2 d, SD 4 d and SD 6 d rats in the hippocampus and in SD 4 d and SD 6 d rats in the frontal cortex (P <0.05), respectively.

CONCLUSIONGSRb1 enhances the expression of somatostatin in sleep deprivation rats and subsequently may improve learning and memory abilities of rats.

Animals ; Brain ; metabolism ; Disease Models, Animal ; Ginsenosides ; pharmacology ; Learning ; drug effects ; Male ; Memory ; drug effects ; Rats ; Rats, Sprague-Dawley ; Sleep Deprivation ; metabolism ; Somatostatin ; metabolism

Objective: To explore the effects of the mu-opioid receptor (MOR) in the paraventricular nucleus (PVN) on the ejaculatory behaviors of male rats and its potential mechanisms. METHODS: Male SD rats with normal ejaculation ability were mated with female ones in hormone-induced estrus. After bilateral PVN microinjection of D-Ala-2-Me-Phe-4-Gly-ol enkephalin (DAGO) or D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH2 (CTAP) with an inserted catheter, the male animals were observed for mount latency (ML), mount frequency (MF), intromission latency (IL), intromission frequency (IF), ejaculation latency (EL), ejaculation frequency (EF), post-ejaculation interval (PEI), and intromission ratio (IR). The lumbar sympathetic nerve activity (LSNA) of the rats was recorded using the PowerLab data acquisition hardware device, and the levels of norepinephrine (NE) in the peripheral plasma were measured by ELISA following microinjection of saline or different doses of DAGO or CTAP. RESULTS: Neither CTAP nor DGAO significantly affected the ML of the male rats (P > 0.05). DGAO remarkably increased IF (P < 0.01) and MF (P < 0.01), prolonged IL (P < 0.01), EL (P < 0.01) and PEI (P < 0.01), and reduced EF (P <0.01) and IR (P < 0.05). On the contrary, CTAP markedly decreased IF (P < 0.01) and MF (P < 0.01), shortened IL (P < 0.01), EL (P < 0.01) and PFI (P < 0.01), and elevated EF (P < 0.01) and IR (P < 0.01). Additionally, DAGO decreased LSNA in a dose-dependent manner and reduced the NE level in the peripheral plasma. CTAP, however, not only offset the effects of DAGO on LSNA, but also significantly increased LSNA. CONCLUSIONS MOR in PVN inhibits ejaculatory behaviors in male rats by weakening LSNA, which has provided some theoretical evidence for the use of highly selective opioids in the treatment of premature ejaculation.
Animals ; Ejaculation ; Enkephalin, Ala(2)-MePhe(4)-Gly(5)-/pharmacology* ; Female ; Male ; Paraventricular Hypothalamic Nucleus/physiology* ; Peptide Fragments/pharmacology* ; Rats ; Rats, Sprague-Dawley ; Receptors, Opioid, mu/physiology* ; Somatostatin/pharmacology* ; Sympathetic Nervous System/physiology*

OBJECTIVETo observe the effect of Fructus Aurantii Immaturus (FAI) on the electro-activity of small intestines in rats, and evaluate the interrelations between the FAI regulating effect and choecystokinin (CCK) and somatostatin (SS).

METHODSMigrating myoelectric complex (MMC) cyclic period, the ratio of the active time to the cyclic period, and the number of the fast wave within the active time per minute were observed between FAI and the normal saline group by external alimentary canal electrodes; the CCK contents in dorsomedial hypothalamic nucleus (DMH), ventromedia hypothalamic nucleus (VMH), lateral hypothalamus area (LHA) and SS in VMH, LHA, paraventricular nucleus (PVN) by using immuno-chemistry technique and micro-image pattern quantitative analysis and scanning system.

RESULTSThe MMC cyclic period shortened, the ratio of the active time to the cyclic period increased and the number of the fast wave within the active time per minute increased in the FAI group, which showed significant difference from the normal saline group; CCK positive neurons were reduced in the areas of DMH, VMH and LHA, SS positive neurons were increased in the areas of VMH, LHA and PVN in the FAI gioup,which showed significant difference compared with the normal saline and the blank control group.

CONCLUSIONFAI can stimulate the electro-reactivity of small intestines. The stimulative effect of FAI might be related to CCK and SS in hypothamus.

Animals ; Central Nervous System Stimulants ; pharmacology ; Cholecystokinin ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Hypothalamus ; drug effects ; metabolism ; Intestine, Small ; drug effects ; physiology ; Myoelectric Complex, Migrating ; drug effects ; Rats ; Somatostatin ; metabolism