No abstract available.
Analgesia* ; Animals ; Fenclonine* ; Mice* ; Naloxone* ; Swimming*

In the present study, we investigated the effect of pretreatment of p-chlorophenylalanine (PCPA), inhibitor of serotonin synthesis, on lipopolysaccharide (LPS)-induced anorexia in rats. First of all, effects of PCPA injection on food intake and body weight in rats were investigated. During 4 days of PCPA injection (300 mg/kg BW once a day), food intake was decreased by 33% and daily gain in body weight was inhibited compared with controls. Twenty-four hours after last PCPA injection, food intake and gain in body weight returned toward almost normal. Pair-feeding to PCPA (PCPAP) injection revealed that body weight of rats in PCPA group was not different from rats in PCPAP groups. To quantify the effects of LPS on food intake and body weight, we administered varying doses (10, 100, 500 microgram/kg BW) of LPS to rats. LPS induced a reduction of food intake and weight loss in a dose dependent manner compared with controls. To evaluate the effects of PCPA pretreatment on LPS injection, rats were treated with PCPA for 4 days (300 mg/kg BW once a day), which was followed by LPS injection for 2 days (500 microgram/kg BW once a day) (PCPA+LPS group), while rats in LPS group had injections with normal saline instead of PCPA for 4 days, which was followed by LPS administration. Rats in control group received 0.9% NaCl for 6 days. LPS decreased food intake by 80% and inhibited gain in body weight, while PCPA pretreated rats showed normalized food intake and gain in weight during the days of LPS injections compared with controls. In conclusion, pretreatment of PCPA prevented LPS-induced anorexia.
Animals ; Anorexia* ; Body Weight ; Eating ; Fenclonine* ; Rats* ; Serotonin* ; Weight Loss

Previously, we have reported that p-chlorophenylalanine (PCPA), a serotonin depletor, profoundly increased pancreatic fluid and bicarbonate secretion but remarkably inhibited pancreatic amylase secretion in anesthetized rats. The present study was performed to verify the detailed effects of PCPA on pancreatic amylase synthesis that is directly related to amylase exocrine secretion. PCPA significantly decreased pancreatic RNA and protein contents as well as the amylase activity. However, pancreatic DNA content, trypsin and chymotrypsin activities were not influenced by the treatment of PCPA. The rate of pancreatic amylase synthesis, which was assessed by the amount of incorporated (35S)-methionine into amylase for 1 h, was also significantly decreased by 44% in PCPA-treated rats. In order to determine whether the PCPA-induced decrease of amylase synthesis resulted from change in the level of amylase mRNA, Northern blot analysis was performed. The mRNA expression level of amylase was also decreased by 48% in the PCPA-treated rats, indicating that the inhibitory effect of PCPA on the synthesis of pancreatic amylase was mainly regulated at a step prior to translation. It was also revealed in SDS-polyacrylamide gel electrophoresis that the qualitative change of amylase was induced by PCPA. The 54 KDa amylase band seems to be degraded into small molecular weight protein bands in PCPA-treated rats, suggesting that the PCPA-induced decrease of amylase may be partly attributed to the degradation of synthesized amylase.
Amylases* ; Animals ; Blotting, Northern ; Chymotrypsin ; DNA ; Electrophoresis ; Fenclonine* ; Molecular Weight ; Pancreas ; Rats* ; RNA ; RNA, Messenger ; Serotonin ; Trypsin

BACKGROUND: Hepatic steatosis is caused by metabolic stress associated with a positive lipid balance, such as insulin resistance and obesity. Previously we have shown the anti-obesity effects of inhibiting serotonin synthesis, which eventually improved insulin sensitivity and hepatic steatosis. However, it is not clear whether serotonin has direct effect on hepatic lipid accumulation. Here, we showed the possibility of direct action of serotonin on hepatic steatosis. METHODS: Mice were treated with para-chlorophenylalanine (PCPA) or LP-533401 to inhibit serotonin synthesis and fed with high fat diet (HFD) or high carbohydrate diet (HCD) to induce hepatic steatosis. Hepatic triglyceride content and gene expression profiles were analyzed. RESULTS: Pharmacological and genetic inhibition of serotonin synthesis reduced HFD-induced hepatic lipid accumulation. Furthermore, short-term PCPA treatment prevented HCD-induced hepatic steatosis without affecting glucose tolerance and browning of subcutaneous adipose tissue. Gene expression analysis revealed that the expressions of genes involved in de novo lipogenesis and triacylglycerol synthesis were downregulated by short-term PCPA treatment as well as long-term PCPA treatment. CONCLUSION: Short-term inhibition of serotonin synthesis prevented hepatic lipid accumulation without affecting systemic insulin sensitivity and energy expenditure, suggesting the direct steatogenic effect of serotonin in liver.
Animals ; Diabetes Mellitus ; Diet ; Diet, High-Fat ; Energy Metabolism ; Fatty Liver ; Fenclonine ; Gene Expression ; Glucose ; Insulin Resistance ; Lipogenesis ; Liver ; Mice ; Obesity ; Serotonin* ; Stress, Physiological ; Subcutaneous Fat ; Transcriptome ; Triglycerides

This study is to explore the possible mechanisms of the antidepressant-like effect of agmatine. By using two traditional "behavior despair" model, tail suspension test and forced swimming test, we examined the effects of some monoamine receptor antagonists (including beta-adrenergic receptor antagonist propranolol, beta-adrenergic receptor antagonist/5-HT1A/1B receptor antagonist pindolol, alpha2-adrenergic receptor antagonists yohimbine and idazoxan and 5-HT3 receptor antagonist tropisetron) on the antidepressant-like action of agmatine in mice. Activity of adenylate cyclase (AC) in the synapse membrane from rat frontal cortex was determined by radioimmunoassay. Single dose of agmatine (5-40 mg x kg(-1), ig) dose-dependently decrease the immobility time in tail suspension test in mice, indicating an antidepressant-like effect. The effect of agmatine (40 mg x kg(-1), ig) was antagonized by co-administration of beta-adrenergic receptor antagonist/5-HT1A/1B receptor antagonist pindolol (20 mg x kg(-1), ip), alpha2-adrenergic receptor antagonists yohimbine (5-10 mg x kg(-1), ip) or idazoxan (4 mg x kg(-1), ip), but not beta-adrenergic receptor antagonist propranolol (5-20 mg x kg(-1), ip) and 5-HT3 receptor antagonist tropisetron (5-40 mg x kg(-1), ip). Agmatine (5-40 mg x kg(-1), ig) also dose-dependently decrease the immobility time in forced swimming test in mice. The effect of agmatine (40 mg x kg(-1), ig) was also antagonized by pindolol (20 mg x kg(-1), ip), yohimbine (5-10 mg x kg(-1), ip), or idazoxan (4 mg x kg(-1), ip). Incubation of agmatine (0.1-6.4 micromol x L(-1)) with the synaptic membrane extracted from rat frontal cortex activated the AC in a dose-dependent manner in vitro. While the effect of agmatine (6.4 micromol x L(-1)) was dose-dependently antagonized by pindolol (1 micromol x L(-1)) or yohimbine (0.25-1 micromol x L(-1)). Chronic treatment with agmatine (10 mg x kg(-1), ig, bid, 2 w) or fluoxetine (10 mg x kg(-1), ig, bid, 2 w) increased the basic activity, as well as the Gpp (NH)p (1-100 micromol x L(-1)) stimulated AC activity in rat prefrontal cortex. These results indicate that regulation on 5-HT1A/1B and alpha2 receptors, and activation AC in the frontal cortex is one of the important mechanisms involving in agmatine's antidepressant-like action.
Adenylyl Cyclases ; metabolism ; Adrenergic alpha-Antagonists ; pharmacology ; Adrenergic beta-Antagonists ; pharmacology ; Agmatine ; administration & dosage ; pharmacology ; Animals ; Antidepressive Agents ; administration & dosage ; pharmacology ; Behavior, Animal ; drug effects ; Depression ; metabolism ; physiopathology ; Dose-Response Relationship, Drug ; Fenclonine ; pharmacology ; Idazoxan ; pharmacology ; Male ; Mice ; Pindolol ; pharmacology ; Random Allocation ; Rats ; Rats, Wistar ; Receptors, Biogenic Amine ; antagonists & inhibitors ; Serotonin 5-HT1 Receptor Antagonists ; Swimming ; Synapses ; enzymology ; Yohimbine ; pharmacology