Effects of fluoxetine administration on mu-opoid receptor immunostaining in the rat forebrain

Fluoxetine is a selective serotonin reuptake inhibitor. Analysis of mu-opioid receptor immunostaining after chronic fluoxetine administration in rats revealed an increase in the density of cells expressing mu-opioid receptors in the caudatus-putamen, the dentate gyrus, the lateral septum and the frontal, parietal and piriform cortices. These data suggest that mu-opioid receptor expression in the rat forebrain is altered by in vivo chronic fluoxetine treatment.     

Effects of high doses of diazepam on carrageenin-induced paw edema in rats

Benzodiazepine (BDZ) receptor sites play a relevant role in immune/inflammatory reactions. Acute BDZ treatments were shown not only to suppress cell proliferation in rat thymus but also to decrease TNF-alpha, IL-1 and IL-6 release from adult mouse macrophages. In the present investigation the effects of acute (10.0 and 20.0 mg/kg) and long-term (10.0 mg kg-1 day-1, for 21 days) diazepam treatment on carrageenin-induced paw edema were studied in rats. The results showed that acute treatment with high doses of diazepam decreased paw edema volume in a dose-dependent manner, and this effect was observed as early as 1 h after the administration of the 20.0 mg/kg dose and continued until the last measurement was performed (8 h). In contrast, long-term diazepam administration did not modify the phlogistic-induced edema. Taken together, these data show that 1) acute diazepam treatment with high doses decreases the volume of the acute inflammatory paw edema developed by the organism as a response to carrageenin-induced injury, and 2) long-term diazepam treatment induces tolerance to this effect. These results are discussed in the light of a possible effect of diazepam on the components of the rat cellular and humoral immune/inflammatory reaction such as T lymphocytes and/or interleukins.     

Modulation of delta9-tetrahydrocannabinol-induced hypothermia by fluoxetine in the rat

We characterized the development of the anti-centromere antibody in a patient prior to the development of CREST (calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, telangiectasias) symptoms. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by immunoblotting (IgG and IgM) of cellular extracts enriched for centromere antigens and indirect immunofluorescence were used to study the anti-centromere immune response. The sera recognized 3 centromere antigens with molecular masses 18,000 (CENP-A), 50,000 (CENP-D), and 80,000 (CENP-B). For CENP-A, IgM was present before the appearance of the IgG response. Anti-CENP-D revealed an IgM response that decreased over time but no IgG, while CENP-B showed an IgG response that strengthened and then weakened over time. The appearance of an anti-centromere nuclear fluorescence pattern correlated with the appearance of IgG anti-CENP-A. Signs and symptoms typical of CREST began about 4 years after antibodies to centromere antigens were found. The development of the CREST syndrome in our patient was preceded by the appearance of anti-centromere autoantibodies. For at least one of the antigens (CENP-A), there was an immunoglobulin class switch from IgM to IgG.     

Effects of fluoxetine and dothiepin on 24-hour activity in depressed patients

The Munich Information Center for Protein Sequences (MIPS-GSF), Martinsried near Munich, Germany, develops and maintains genome oriented databases. It is commonplace that the amount of sequence data available increases rapidly, but not the capacity of qualified manual annotation at the sequence databases. Therefore, our strategy aims to cope with the data stream by the comprehensive application of analysis tools to sequences of complete genomes, the systematic classification of protein sequences and the active support of sequence analysis and functional genomics projects. This report describes the systematic and up-to-date analysis of genomes (PEDANT), a comprehensive database of the yeast genome (MYGD), a database reflecting the progress in sequencing the Arabidopsis thaliana genome (MATD), the database of assembled, annotated human EST clusters (MEST), and the collection of protein sequence data within the framework of the PIR-International Protein Sequence Database (described elsewhere in this volume). MIPS provides access through its WWW server (http://www.mips.biochem.mpg.de) to a spectrum of generic databases, including the above mentioned as well as a database of protein families (PROTFAM), the MITOP database, and the all-against-all FASTA database.     

Neurogenic inflammation in the gastrointestinal tract of the rat

To estimate the risk of repeat low birthweight deliveries among women whose first child was very low birthweight (less than 1500 g), a retrospective cohort of women who had their first and second children in Washington state between 1984 and 1991 was studied. After adjustment for potential confounding factors, a woman whose first infant was very low birthweight experienced an 11.5-fold increased risk of delivering a low birthweight (less than 2500 g) second infant (relative risk 11.5, 95% confidence interval 5.4 to 24.4). Women with a very low birthweight first infant also had a significantly increased risk of repeat very low birthweight infant (p < 0.0001). Women with a previous very low birthweight delivery are at increased risk of repeat low and very low birthweight infants. This high-risk group may benefit from education regarding recurrence risk and modification of factors associated with low birthweight, as well as good prenatal care.     

Effects of fluoxetine on the development of lung metastases induced by operative stress in rats

Experiments were performed in order to evaluate the effects of fluoxetine, a selective inhibitor of neural serotonin transporter antidepressant, on the development lung metastases in rats subjected to laparotomy and injected (i.v.) with 10(4) Walker 256 (W-256) carcinosarcoma cells. The number of metastatic nodules on the surface of the lungs, as well as the percentage-area of metastases in the frontal section through pulmonary hilus were increased in rats subjected to sham-surgery or laparotomy. Treatment with fluoxetine (5 mg/kg) partially reversed those adverse effects of surgery, but the difference was clearer when it was administered before surgery was performed. Survival periods were also assessed and fluoxetine was found to decrease the lethality of rats exposed to surgery.     

Daily fluoxetine administration impairs avoidance learning in the rat without altering sensory thresholds

1. Male rats given daily intraperitoneal injections of fluoxetine (10 mg/kg) were slower to escape foot shock by jumping a low barrier. 2. When switched to a shuttle task requiring two crosses to terminate shock, the FLU-treated animals failed to learn in 55 trials. 3. A second experiment found FLU-treated animals could learn a one-way avoidance response, but were significantly slower to learn than control animals. 4. FLU-treated animals were no different than controls on tests of sensory thresholds for foot shock or heat. 5. Tests of motor behaviors revealed no differences in latency to traverse a narrow beam to reach a goal box, however FLU-treated animals were less active in an open field. 6. Several hypotheses can account for these data, the most promising being that a central motivational system (fear) is less active in FLU-treated animals.     

Effects of physiological hypercortisolemia on the regulation of lipolysis in subcutaneous adipose tissue

Cortisol is known to increase whole body lipolysis, yet chronic hypercortisolemia results in increased fat mass. The main aim of the study was to explain these two apparently opposed observations by examining the acute effects of hypercortisolemia on lipolysis in subcutaneous adipose tissue and in the whole body. Six healthy subjects were studied on two occasions. On one occasion hydrocortisone sodium succinate was infused i.v. to induce hypercortisolemia (mean plasma cortisol concentrations, 1500 +/- 100 vs. 335 +/- 25 nmol/L; P < 0.001); on the other occasion (control study) no intervention was made. Lipolysis in the s.c. adipose tissue of the anterior abdominal wall was studied by measurement of arterio-venous differences, and lipolysis in the whole body was studied by constant infusion of [1,2,3-2H5]glycerol for measurement of the systemic glycerol appearance rate. Hypercortisolemia led to significantly increased arterialized plasma nonesterified fatty acid (NEFA; P < 0.01) and blood glycerol concentrations (P < 0.05), with an increase in systemic glycerol appearance (P < 0.05). However, in s.c. abdominal adipose tissue, hypercortisolemia decreased veno-arterialized differences for NEFA (P < 0.05) and reduced NEFA efflux (P < 0.05). This reduction was attributable to decreased intracellular lipolysis (P < 0.05), reflecting decreased hormone-sensitive lipase action in this adipose depot. Hypercortisolemia caused a reduction in arterialized plasma TAG concentrations (P < 0.05), but without a significant change in the local extraction of TAG (presumed to reflect the action of adipose tissue lipoprotein lipase). There was no significant difference in plasma insulin concentrations between the control and hypercortisolemia study. Site-specific regulation of the enzymes of intracellular lipolysis (hormone-sensitive lipase) and intravascular lipolysis (lipoprotein lipase) may explain the ability of acute cortisol treatment to increase systemic glycerol and NEFA appearance rates while chronically promoting net central fat deposition.     

Effects of fluoxetine versus bright light in the treatment of seasonal affective disorder

BACKGROUND: Disturbances of serotonergic neurotransmission appear to be particularly important for the pathophysiology of winter depression. This study investigated whether fluoxetine has antidepressant effects comparable to bright light in the treatment of seasonal affective disorder (winter type). METHOD: A randomized, parallel design was used with rater and patients blind to treatment conditions. One week of placebo (phase I) was followed by 5 weeks of treatment (phase II) with fluoxetine (20 mg per day) and a placebo light condition versus bright light (3000 lux, 2 h per day) and a placebo drug. There were 40 patients (20 in each treatment condition) suffering from seasonal affective disorder (SAD) according to DSM-III-R who had a total score on the Hamilton Depression Scale of at least 16. RESULTS: Forty patients entered phase II and 35 completed it (one drop-out in the fluoxetine group and four in the bright light group). Fourteen (70%) of the patients treated with bright light and 13 (65%) of those treated with fluoxetine were responders (NS). The remission rate in the bright light group tended to be superior (bright light 50%, fluoxetine 25%; P = 0.10). Light therapy improved HDRS scores significantly faster, while fluoxetine had a faster effect on atypical symptoms. Light treatment in the morning produced a significantly faster onset of improvement, but at the end of treatment the time of light application seemed not to be crucial. CONCLUSION: Both treatments produced a good antidepressant effect and were well tolerated. An apparently better response to bright light requires confirmation in a larger sample.     

Hormonal manipulation of carrageenin-induced pyresis in rats,

The intensity of the hyperthermic response in rats promoted by subplantar injections of 1 mg of carrageenin is directly related to the irritant properties of the type of carrageenin. The overall pyretic response is more dramatic in female rats than in male rats. Subtle changes in the time-course hyperthermic profiles are seen after hormonal modifications.     

Effects of rat amylin on renal function in the rat

After the establishment of the theoretical and clinical background of SIRS, the mechanism of organ failure induction during the perioperative period was gradually clarified. The deterioration of the mutual regulation of cytokines after surgical stress is considered to be a major cause of organ failure. Hypercytokinemia is one of the pathophysiological features after surgical stress, and thus a new therapeutic approach ameliorating the impaired cytokine network has been applied instead of direct targeting therapy for impaired organs. Organ failure can be anticipated based on a precise assessment of the severity of SIRS or CARS. For example, to prevent postsurgical hepatic failure it is important to minimize surgical stress by assessing the preoperative liver reserve capacity. Excessive surgical stress coupled with underestimation of liver function may result in primary multiple organ failure (MOF) after hepatic surgery. Secondary MOF after postsurgical infection may implicate the bacterial translocation mechanism. At present, only CHDF is considered to be a promising therapy for hypercytokinemia. Therefore the prophylactic approach cannot be neglected. The monitoring of cytokines such as IL-6 during the perioperative period provides valuable information for the prediction of organ failure.     

Effects of airway inflammation on cough response in the guinea pig

We have developed a guinea pig model for cough related to allergic airway inflammation. Unanesthetized animals were exposed to capsaicin aerosols for 10 min, and cough frequency was counted during this period. The cough evaluation was performed by the following three methods: visual observation, acoustic analysis, and monitoring of pressure changes in the body chamber. These analyses clearly differentiated a cough from a sneeze. To elucidate the relationship between cough response and airway inflammation, animals were immunosensitized and multiple challenged. Sensitized guinea pigs presented no specific changes microscopically, but multiple-challenged animals showed an increased infiltration of inflammatory cells into the airway. Cough number in response to capsaicin increased significantly from 4.7 +/- 1.4 coughs/10 min in normal animals to 10.6 +/- 2.0 coughs/10 min in sensitized animals and further to 22.8 +/- 1.3 coughs/10 min in multiple-challenged animals. This augmented cough frequency was significantly inhibited by the inhalation of tachykinin-receptor antagonists and by oral ingestion, but not inhalation, of codeine phosphate. The results suggest that airway inflammation potentiates an elevation of cough sensitivity in this model.     

The effects of mexiletine, desipramine and fluoxetine in rat models involving central sensitization

The lutropin receptor (LHR) is a G protein-coupled receptor in which high affinity ligand binding occurs to the relatively large extracellular N-terminal domain. Various portions of the receptor have been mapped for their relative importance in localization and in hormone-mediated signaling. There is, however, a paucity of information available on the intracellular loops (ICL), where, along with the C-terminal cytoplasmic tail, G protein coupling is expected to occur. Site-directed mutagenesis was used to investigate the role of several conserved ionizable groups and one tyrosyl residue in ICLs I-III of the rat LHR. The pSVL expression vector, containing the LHR cDNA (wild-type and mutants), was transiently transfected into COS-7 cells, and human choriogonadotropin (hCG) binding and hCG-mediated cAMP production were determined. Several point mutants of amino acid residues in ICL II were prepared and characterized with the following results: replacements of Lys-455 and of His-460 with Glu gave mutant LHRs that failed to localize or fold properly at the cell surface as evidenced by the lack of significant binding to intact cells, although hCG binding could be detected in broken cell preparations, and a neighboring Arg-459 --> Glu replacement had no apparent effect on receptor trafficking, hCG binding or hCG-mediated cAMP-production. A reversal mutant in ICL II in which Glu-441, at the boundary of transmembrane helix III and ICL II, and His-460, at the interface between ICL II and transmembrane helix IV, were interchanged, exhibited hCG binding to intact cells, but the maximal cAMP level at high concentrations of ligand was less than that obtained with COS-7 cells transfected with wild-type LHR. The total number of cell surface receptors determined with the reversal mutant was less than that found with wild-type LHR. This difference, however, is not believed to be responsible for the reduced signaling, since maximal cAMP responses to hCG were obtained with comparable receptor densities of wild-type and various mutant LHRs. Other single replacements in ICL I, Lys-368 --> Glu and to Gln, and in ICL III, Arg-526 --> Glu and Tyr-528 --> Ser, resulted in mutant LHRs with characteristics of wild-type LHR in trafficking, hCG binding and hCG-mediated cAMP production. These findings suggest an important functional role of several amino acid residues in ICL II of LHR.     

Effects of fluoxetine given chronically on the responsiveness of 5-HT receptor subpopulations to their agonists

The effect of chronic treatment (5 and 10 mg/kg i.p., twice daily, 14 days) with fluoxetine (FLU), an antidepressant drug which selectively inhibits the reuptake of 5-hydroxytryptamine (5-HT), on the responsiveness of 5-HT receptor subpopulations to their agonists in rats and mice was examined. FLU had no effect on the hypothermia (in mice) and the behavioural syndrome (in rats) induced by 8-OH-DPAT (a 5-HT1A agonist). The m-CPP-induced hypothermia in mice (a 5-HT1B effect) was increased by FLU given chronically. FLU in a single dose decreased that effect. FLU given chronically attenuated the m-CPP-induced hypoactivity in rats (a 5-HT1C effect). The effects mediated by 5-HT2 receptors (L-5-HTP-induced head twitches in mice; fenfluramine-, m-CPP- and TFMPP-induced hyperthermias in rats) were reduced by chronic FLU. The above results indicate that FLU given chronically has no effect on the responsiveness of 5-HT1A receptors, increases the responsiveness of 5-HT1B receptors and decreases those of 5-HT1C and 5-HT2 receptors.     

The comparison of fluoxetine and nisoxetine with tricyclic antidepressants in blocking the neurotoxicity of p-chloroamphetamine and 6-hydroxydopamine in the rat brain

Fluoxetine prevents the loss of 5-hydroxytryptamine (5HT) uptake in synaptosomes of cerebral cortex after intraperitoneally administered p-chloroamphetamine (p-CA) with an ED50 of 3.8 mg/kg i.p. in rats. However, at 50 mg/kg, it does not prevent the loss of norepinephrine (NE) uptake in synaptosomes of hypothalamus after intraventricularly administered 6-hydroxydopamine (6-OHDA). Nisoxetine, on the other hand, centrally protects NE uptake from the neurotoxic effect of 6-OHDA with an ED50 value of 5 mg/kg i.p. At 50 mg/kg, it gives only 35% protection of 5HT uptake from the neurotoxic effect of p-CA. In comparison with the ED50 values of tricyclic antidepressants, both fluoxetine and nisoxetine are more potent and selective blockers of neurotoxicity resulting from the central actions of p-CA and 6-OHDA, respectively, in vivo.     

Mast cell recruitment after subcutaneous injection of RANTES in the sole of the rat paw

Granulocyte colony-stimulating factor (G-CSF)-induced alteration of phosphoprotein during differentiation of HL-60 cells was studied. From the two-dimensional gel electrophoresis analysis of phosphoproteins, a 45 kD phosphoprotein in the cytosolic fraction of DMSO-pretreated HL-60 cells was rapidly dephosphorylated by the addition of G-CSF. This 45 kD phosphoprotein migrated into four or five spots between 4.5 and 5.5 pI. The dephosphorylation of 45 kD protein was observed within at least 10 min and reached a maximum at 60 min. Phosphoamino acid analysis showed that only serine residue of 45 kD phosphoprotein was phosphorylated, suggesting that G-CSF induced an activation of serine phosphatase. Furthermore, Staurosporine and calphostin C inhibited the phosphorylation of 45 kD protein, suggesting that protein kinase C or its downstream kinase(s) is involved in the phosphorylation of 45 kD protein. These results indicate that G-CSF causes dephosphorylation of a 45 kD cytosolic phosphoprotein which may play a role in signal transduction of G-CSF.     

Effect of continuous spinal remifentanil infusion on behaviour and spinal glutamate release evoked by subcutaneous formalin in the rat

Four mutants of Arabidopsis thaliana that are deficient in adenine phosphoribosyl transferase (APRT) activity have been isolated by selecting for germination of seeds and growth of the plantlets on a medium containing 2,6-diaminopurine (DAP), a toxic analog of adenine. In all mutants, DAP resistance is due to a recessive nuclear mutation at a locus designated apt. The mutants are male sterile due to pollen abortion after meiosis. Furthermore, it has been shown that metabolism of cytokinins is impaired in the mutant BM3, which has the lowest level of APRT activity among the mutants tested. However, three different cDNAs encoding APRT have been isolated in A. thaliana and this raised the question of the nature of the mutation which results in low APRT activity. The mutation was genetically mapped to chromosome I and lies within 6 cM of the phenotypic marker dis2, indicating that the mutation affects the APT1 gene, a result confirmed by sequencing of mutant alleles. The mutation in the allele apt1-3 is located at the 5' splicing site of the third intron, and eliminates a BstNI restriction site, as verified by Southern blotting and PCR fragment length analysis.     

Delayed and prolonged vascular leakage in inflammation: the effects of dehydromonocrotaline on blood vessels in the rat cremaster

Local application of dehydromonocrotaline to the rat cremaster produces a delayed prolonged increase in vascular permeability with a time course similar to that of the pulmonary oedema seen after intravenous injection of the same substance. Study of the injured area by the carbon labelling technique and by electron microscopy shows that the increased permeability involves both capillaries and venules of all sizes within the region exposed to dehydromonocrotaline. The vascular leakage appears to be due to a direct effect on the endothelium of small blood vessels. Carbon deposition in labelled capillaries and venules is predominantly intramural and indicative of increased vascular permeability. Accumulation of carbon within the lumen of capillaries is uncommon, and accounts for only a small fraction of total capillary labelling. The findings indicate that capillaries are a major source of inflammatory exudate in this type of injury and suggest that the importance of leakage from capillaries has been underestimated in other types of delayed prolonged increase in vascular permeability.