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*

Mounting evidence supports an important role of chemokines, produced by spinal cord astrocytes, in promoting central sensitization and chronic pain. In particular, CCL2 (C-C motif chemokine ligand 2) has been shown to enhance N-methyl-D-aspartate (NMDA)-induced currents in spinal outer lamina II (IIo) neurons. However, the exact molecular, synaptic, and cellular mechanisms by which CCL2 modulates central sensitization are still unclear. We found that spinal injection of the CCR2 antagonist RS504393 attenuated CCL2- and inflammation-induced hyperalgesia. Single-cell RT-PCR revealed CCR2 expression in excitatory vesicular glutamate transporter subtype 2-positive (VGLUT2) neurons. CCL2 increased NMDA-induced currents in CCR2/VGLUT2 neurons in lamina IIo; it also enhanced the synaptic NMDA currents evoked by dorsal root stimulation; and furthermore, it increased the total and synaptic NMDA currents in somatostatin-expressing excitatory neurons. Finally, intrathecal RS504393 reversed the long-term potentiation evoked in the spinal cord by C-fiber stimulation. Our findings suggest that CCL2 directly modulates synaptic plasticity in CCR2-expressing excitatory neurons in spinal lamina IIo, and this underlies the generation of central sensitization in pathological pain.
Animals ; Benzoxazines ; pharmacology ; therapeutic use ; Chemokine CCL2 ; antagonists & inhibitors ; genetics ; metabolism ; pharmacology ; Excitatory Amino Acid Agents ; pharmacology ; Excitatory Amino Acid Agonists ; pharmacology ; Female ; Freund's Adjuvant ; toxicity ; Hyperalgesia ; chemically induced ; metabolism ; prevention & control ; Long-Term Potentiation ; drug effects ; physiology ; Luminescent Proteins ; genetics ; metabolism ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Transgenic ; Myelitis ; chemically induced ; drug therapy ; metabolism ; Neurons ; drug effects ; Pain Management ; Somatostatin ; genetics ; metabolism ; Spinal Cord ; cytology ; Spiro Compounds ; pharmacology ; therapeutic use ; Vesicular Glutamate Transport Protein 2 ; genetics ; metabolism ; Vesicular Inhibitory Amino Acid Transport Proteins ; genetics ; metabolism

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

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

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

OBJECTIVETo compare the effect of three preparations of xiaoyao formula (xiaoyao capsule, xiaoyao pill and Xiaoyao decoction) on soothing liver and strengthening spleen.

METHODThe liver depression and spleen deficiency rat model were established by forcing swimming, confining movement test and feeding on alternate days. The rats were randomly divided into eight groups, namely the blank group, the model group, the Cisapride group (2.7 mg x kg(-1)), the xiaoyao decoction group (1.62 g x kg(-1)), the xiaoyao pill group (1.62 g x kg(-1)) and the Xiaoyao capsule groups of high dose (3.24 g x kg(-1)), medium dose (1.62 g x kg(-1)) and low dose (0.81 g x kg(-1)), with intragastric administration for 3 weeks. The contents of NE, DA, 5-HT in serum were measured by HPLC-electrochemical detection method. The contents of motilin (MTL) and somatostation (SS) in plasma was determined by radioimmunassay. The expressions of MTL and SS in tissue were determined by immunohistochemical method.

RESULTThe contents of NE and MTL in the xiaoyao decoction group was significantly higher than that in the model group, while the content of 5-HT and SS was significantly lower than that in the model group (P < 0.01). The expression of MTL in the xiaoyao capsule group (1.62 g x kg(-1)) was significantly higher than that in the model group and the contents of 5-HT and SS was significantly lower than that in the model group (P < 0.05). The mean optical density of MTL in gastrointestinal tissue of rats in the xiaoyao decoction group and the xiaoyao capsule group (1.62 g x kg(-1)) was remarkably higher than that in the model group, while the expression of SS was notably lower than that in the model group (P < 0.05).

CONCLUSIONAll of the three preparations of Xiaoyao formula have the effect on soothing liver and strengthening spleen. Xiaoyao decoction shows better effect than xiaoyao capsule with same dosage, while xiaoyao capsule shows better effect than xiaoyao pill with same dosage.

Animals ; Body Weight ; drug effects ; Drugs, Chinese Herbal ; pharmacology ; Intestines ; drug effects ; metabolism ; Liver ; drug effects ; metabolism ; Male ; Motilin ; metabolism ; Rats ; Somatostatin ; metabolism ; Spleen ; drug effects ; metabolism ; Stomach ; drug effects ; metabolism

BACKGROUNDThe aim of this study was to investigate the possible effect of somatostatin on the liver function of recipients undergoing living donor liver transplantation.

METHODSForty recipients were randomized into group A (n = 20) and group B (n = 20). Recipients in group A received no somatostatin whereas somatostatin was administrated for recipients in group B perioperatively. Liver function, the plasma concentration of endothelin-1 and nitric oxide, the intragraft expressions of endothelin-1 and inducible nitric oxide syntheses at 2 hours after declamping of the portal vein were compared between the two groups.

RESULTSCompared to group A, alanine transaminase values in group B were significantly reduced at 2 hours after portal vein declamping, at the end of the operation and postoperation day 1 (P < 0.05), whereas aspartate aminotransferase values in group B decreased at 30 minutes after portal vein clamping, at 2 hours after portal vein declamping and at the end of the operation (P < 0.05). Total bilirubin values in group B were reduced significantly at 2 hours after portal vein declamping and at the end of the operation when compared to group A (P < 0.05). Intragraft expression of endothelin-1 was significantly downregulated at 2 hours after declamping of the portal vein accompanied with a reduction of plasma concentration of endothelin-1 in the peripheral blood (P < 0.05).

CONCLUSIONSSomatostatin had a protective effect on liver function during the early phase after declamping of portal vein for recipients undergoing living donor liver transplantation, and the possible mechanism might be partially attributed to the downregulation of endothelin-1.

Adult ; Down-Regulation ; drug effects ; Endothelin-1 ; blood ; Female ; Hormones ; pharmacology ; therapeutic use ; Humans ; Immunohistochemistry ; Liver ; drug effects ; Liver Transplantation ; methods ; Living Donors ; Male ; Middle Aged ; Nitric Oxide ; blood ; Somatostatin ; pharmacology ; therapeutic use

OBJECTIVETo investigate the effects of SOM230, a new somatostatin analogue, on the proliferation of hepatocellular carcinoma (HCC) cell line HepG2 in vitro and in vivo, and explore the mechanism underline the necrosis of tumors.

METHODSMTT, TdT-mediated dUTP nick end labeling assay (TUNEL) and flow cytometric assay were used to measure the effects of SOM230 on the proliferation and apoptosis of HCC HepG2 cells. Nude mice bearing HCC xenografts of the HepG2 cell line were treated with SOM230 (100 microg/kg/d subcutaneously injection) and saline as a control for eight weeks. The mass and percentage of necrotic volume of the HCC xenografts in nude mice were determined. Western blot was used to detect SSTR2 in HCC xenografts. Immunohistochemical method was used to detect the expression sites of SSTR2 and VEGF in HCC xenografts. ELISA was used to detect the levels of TNFalpha.

RESULTSNo proliferation and apoptosis of HepG2 cells were induced by SOM230 in vitro (F = 0.16, P more than 0.05). The percentage of necrotic volume in SOM230 were significantly higher than that of control group (73.4%+/-7.0% vs 30.2%+/-14.0%, t = -8.02, P more than 0.01). SSTR2 was expressed in blood sinus of HCC xenografts in nude mice. There was no significance difference in the level of SSTR2 expression between SOM230 group and saline treated group. VEGF expression in xenografts was down-regulated by SOM230 treatment. SOM230 treatment did not affect the level of TNFalpha in HCC xenografts (t = -0.24, P more than 0.05).

CONCLUSIONSSOM230 can induce massive necrosis of HCC xenografts only after the blockage of blood flow through down-regulation of VEGF mediated by SSTR2.

Animals ; Antineoplastic Agents ; administration & dosage ; pharmacology ; Carcinoma, Hepatocellular ; blood supply ; metabolism ; pathology ; Cell Proliferation ; drug effects ; Disease Models, Animal ; Flow Cytometry ; Gene Expression Regulation, Neoplastic ; Hep G2 Cells ; Humans ; Immunohistochemistry ; Injections, Subcutaneous ; Liver Neoplasms ; blood supply ; metabolism ; pathology ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Neoplasm Transplantation ; Random Allocation ; Receptors, Somatostatin ; metabolism ; Somatostatin ; administration & dosage ; analogs & derivatives ; pharmacology ; Vascular Endothelial Growth Factor A ; metabolism ; Xenograft Model Antitumor Assays

OBJECTIVETo study the regulative action of mica monomer powder preparation on the chief and parietal cells as well as G and D cells in the gastric mucosa of the experimental atrophic gastritis (CAG) rats.

METHODSIntervention therapy was given to the experimental CAG rats at three different doses of mica monomer powder preparation to evaluate the changes of chief and parietal cells as well as G and D cells in the gastric mucosa and the histopathological changes of gastric mucosa.

RESULTSMica monomer powder preparation at three different doses could increase the amount of chief and parietal cells as well as G and D cells in gastric mucosa of the experimental CAG rats and alleviate and control the inflammation of gastric mucosa and the atrophy of gastric mucosa glands. Especially, better effects were shown in the mid and high dose groups.

CONCLUSIONMica has the pharmacological action of protecting the gastric mucosa, enhancing blood flow of the gastric mucosa, and consequently improving the inflammatory responses of the gastric mucosa. One of the mechanisms is associated with promoting the secretion of gastric acid and gastric pepsin and regulating the neuroendocrine mechanism including gut hormone secretion (gastrin and somatostatin) by increasing the number of chief and parietal cells as well as G and D cells.

Aluminum Silicates ; pharmacology ; Animals ; Cell Count ; Chief Cells, Gastric ; drug effects ; pathology ; Chronic Disease ; Gastric Mucosa ; drug effects ; pathology ; Gastrin-Secreting Cells ; drug effects ; pathology ; Gastritis, Atrophic ; pathology ; Inflammation ; Parietal Cells, Gastric ; drug effects ; pathology ; Powders ; Rats ; Rats, Sprague-Dawley ; Somatostatin-Secreting Cells ; drug effects ; pathology

OBJECTIVETo investigate the mechanism of increasing chemosensitivity of gallbladder carcinoma stimulated by somatostatin.

METHODSGBC-SD cells were divided into four groups: SST-alone-treated group, Doxorubicin (DOX)-alone-treated group and co-treated group (co-treatment of SST and DOX). In the control group, the cells were cultivated by medium only. In SST-alone-treated group, the cells were cultivated by medium with SST in the concentration of 75 microg/ml. In DOX-alone-treated group, the cells were cultivated by medium with DOX in the gradient concentrations of 5, 10, 20 microg/ml. In the co-treated group, cells were first cultivated by medium with 75 microg/ml SST for 24 h, followed by the addition of DOX in the gradient concentrations mentioned above. Cell viability curve was measured by MTT assay at 24, 48, 72 and 96 h, respectively. Meanwhile, the alterations of protein expressions of ICBP90 and Topo IIalpha after treatment of SST were examined by Western blot.

RESULTSThe treatment of SST alone on GBC-SD cells did not exert significantly inhibitory effect compared to the control group (P > 0.05). However, 24 h after the treatment of SST, the protein expressions of ICBP90 and Topo IIalpha were both up-regulated (P < 0.05).

CONCLUSIONUp-regulated the expression of ICBP90 by somatostatin maybe the cause of overexpression of Topo IIalpha, which leads to the enhanced lethal effect of DOX.

Antigens, Neoplasm ; metabolism ; Apoptosis ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; DNA Topoisomerases, Type II ; metabolism ; DNA-Binding Proteins ; metabolism ; Doxorubicin ; pharmacology ; Drug Interactions ; Drug Resistance, Neoplasm ; drug effects ; Gallbladder Neoplasms ; drug therapy ; metabolism ; pathology ; Humans ; Somatostatin ; pharmacology