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  • 1
    Electronic Resource
    Electronic Resource
    Serotonergic Stimulation of Corticotropin-Releasing Hormone and Pro-Opiomelanocortin Gene Expression (2002)
    Oxford, UK : Blackwell Science, Ltd
    Journal of neuroendocrinology 14 (2002), S. 0 
    Details
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The neurotransmitter serotonin (5-HT) stimulates adrenocorticotropic hormone (ACTH) secretion from the anterior pituitary gland via activation of central 5-HT1 and 5-HT2 receptors. The effect of 5-HT is predominantly indirect and may be mediated via release of hypothalamic corticotropin-releasing hormone (CRH). We therefore investigated the possible involvement of CRH in the serotonergic stimulation of ACTH secretion in male rats. Increased neuronal 5-HT content induced by systemic administration of the precursor 5-hydroxytryptophan (5-HTP) in combination with the 5-HT reuptake inhibitor fluoxetine raised CRH mRNA expression in the paraventricular nucleus (PVN) by 64%, increased pro-opiomelanocortin (POMC) mRNA in the anterior pituitary lobe by 17% and stimulated ACTH secretion five-fold. Central administration of 5-HT agonists specific to 5-HT1A, 5-HT1B, 5-HT2A or 5-HT2C receptors increased CRH mRNA in the PVN by 15–50%, POMC mRNA in the anterior pituitary by 15–27% and ACTH secretion three- to five-fold, whereas a specific 5-HT3 agonist had no effect. Systemic administration of a specific anti-CRH antiserum inhibited the ACTH response to 5-HTP and fluoxetine and prevented the 5-HTP and fluoxetine-induced POMC mRNA response in the anterior pituitary lobe. Central or systemic infusion of 5-HT increased ACTH secretion seven- and eight-fold, respectively. Systemic pretreatment with the anti-CRH antiserum reduced the ACTH responses to 5-HT by 80% and 64%, respectively. It is concluded that 5-HT via activation of 5-HT1A, 5-HT2A, 5-HT2C and possibly also 5-HT1B receptors increases the synthesis of CRH in the PVN and POMC in the anterior pituitary lobe, which results in increased ACTH secretion. Furthermore, the results indicate that CRH is an important mediator of the ACTH response to 5-HT.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2826.2002.00839.x
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  • 2
    Electronic Resource
    Electronic Resource
    Serotonin Stimulates Hypothalamic mRNA Expression and Local Release of Neurohypophysial Peptides (2003)
    Oxford, UK : Blackwell Science, Ltd
    Journal of neuroendocrinology 15 (2003), S. 0 
    Details
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The neurotransmitter serotonin (5-HT) stimulates the secretion of vasopressin and oxytocin, and 5-HT is involved in the mediation of the vasopressin and oxytocin response to stress. In male Wistar rats, we investigated the 5-HT receptors involved in the 5-HT-induced increase of mRNA expression of vasopressin and oxytocin in the hypothalamic paraventricular nucleus (PVN) and supraoptic nucleus (SON). The 5-HT precursor, 5-hydroxytryptophan, injected in combination with the 5-HT reuptake inhibitor, fluoxetine, increased oxytocin mRNA expression in the PVN, and the concentration of vasopressin and oxytocin in plasma, whereas mRNA in the SON was not affected. Intracerebroventricular infusion of 5-HT agonists selective for the 5-HT1A, 5-HT1B, 5-HT2A and 5-HT2C receptor increased oxytocin mRNA in the SON and PVN. Infusion of agonists selective for the 5-HT2A + 2C receptor increased vasopressin mRNA in the PVN, whereas none of the 5-HT agonists affected vasopressin mRNA in the SON. All the 5-HT agonists infused increased peripheral oxytocin concentration and vasopressin was increased by stimulation of the 5-HT2A, 5-HT2C and 5-HT3 receptor. Intracerebroventricular infusion of 100 nmol 5-HT increased the extracellular hypothalamic concentration of vasopressin as measured by microdialysis in the PVN. To evaluate the involvement of hypothalamic-pituitary system in the 5-hydroxytryptophan and fluoxetine-induced vasopressin secretion, rats were immunoneutralized with a specific anti-corticotropin-releasing hormone antiserum. This treatment reduced plasma vasopressin and oxytocin responses. We conclude that stimulation with 5-hydroxytryptophan or 5-HT agonists increases mRNA expression of oxytocin in the PVN and the SON via stimulation of at least 5-HT1A, 5-HT1B, 5-HT2A and 5-HT2C receptors. Vasopressin mRNA in the PVN was increased only via the 5-HT2 receptor, whereas vasopressin mRNA in the SON does not seem to be affected by 5-HT stimulation. Corticotropin-releasing hormone appears to be partly involved in the mediation of 5-HT induced vasopressin and oxytocin secretion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2826.2003.01032.x
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  • 3
    Electronic Resource
    Electronic Resource
    Histamine and Prostaglandin Interaction in Regulation of Oxytocin and Vasopressin Secretion (2003)
    Oxford, UK : Blackwell Science, Ltd
    Journal of neuroendocrinology 15 (2003), S. 0 
    Details
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Prostaglandins and histamine in the hypothalamus are involved in the regulation of oxytocin and vasopressin secretion, and appear to be involved in the mediation of pituitary hormone responses to immunochallenges. Therefore, we investigated in conscious male rats: (i) whether blockade of H1 or H2 receptors affected the oxytocin and vasopressin responses to prostaglandins and (ii) whether blockade of prostaglandin synthesis affected the oxytocin and vasopressin responses to histamine or to Escherichia coli lipopolysaccharide (LPS), in order to determine any interaction between prostaglandins and histamine in the hypothalamus. Oxytocin secretion was dose-dependently stimulated by intracerebroventricular infusion of 1 or 5 µg of PGE1, PGE2 or PGF2α, with PGE2 being the most potent of the compounds used. Prior central infusion of the H1 receptor antagonist mepyramine or the H2 receptor antagonist cimetidine significantly inhibited the oxytocin response to all three prostaglandins by approximately 50%. Vasopressin secretion was increased by PGE1 but not by PGE2 or PGF2α. The stimulatory effect of PGE1 was almost annihilated by prior administration of mepyramine or cimetidine. Central infusion of histamine or immunochallenge with LPS administered intraperitoneally increased oxytocin and vasopressin secretion four- and two-fold, respectively. Pretreatment with systemic injection of the prostaglandin synthesis inhibitor indomethacin dose-dependently reduced the oxytocin response and prevented the vasopressin response to histamine or LPS. We conclude that histamine and PGE1, PGE2 or PGF2α interact in the regulation of oxytocin secretion, whereas histamine and only PGE1 interact in the regulation of vasopressin secretion. Furthermore, histamine as well as LPS may affect oxytocin and vasopressin neurones via activation of prostaglandins, probably in the hypothalamic supraoptic nucleus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2826.2003.01079.x
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  • 4
    Electronic Resource
    Electronic Resource
    Serotonin Receptors Involved in Vasopressin and Oxytocin Secretion (2003)
    Oxford, UK : Blackwell Science Ltd
    Journal of neuroendocrinology 15 (2003), S. 0 
    Details
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Serotonin (5-HT), 5-HT agonists, the 5-HT precursor 5-hydroxytryptophan, 5-HT-releasers and -reuptake inhibitors stimulate the release of vasopressin and oxytocin. We investigated the involvement of 5-HT receptors in the serotonergic regulation of vasopressin and oxytocin secretion. Vasopressin and oxytocin secretion was stimulated by 5-HT, the 5-HT1A+1B+5A+7 agonist 5-carboxamidotryptamine (5-CT), the 5-HT2A+2C agonist DOI, the 5-HT2C+2A agonist mCPP, the 5-HT2C agonist MK-212, the 5-HT3 agonist SR 57277 and the 5-HT4 agonist RS 67506. The 5-HT1A agonist 8-OH-DPAT, which had no effect on vasopressin secretion, stimulated oxytocin secretion. The 5-HT-induced release of vasopressin and oxytocin was inhibited by central infusion of the 5-HT antagonists WAY 100635 (5-HT1A), LY 53857 (5-HT2A+2C), ICS 205-930 (5-HT3+4) and RS 23597 (5-HT4). The 5-HT2+6+7 antagonist metergoline in combination with the 5-HT1A+2+7 antagonist methysergide inhibited the stimulatory effect of 5-CT on both hormones, whereas the 5-HT1A+1B antagonist cyanopindolol only inhibited the oxytocin response. The 5-HT2A antagonist 4-(4-flourobenzoyl)-1-(4-phenylbutyl)-piperidine oxalate had no effect on DOI-induced hormone response. The 5-HT2C antagonist Y 25130 partly inhibited the stimulating effect of MK-212. ICS 205-930 and RS 23597 inhibited vasopressin and oxytocin secretion induced by RS 67506. WAY 100635 inhibited 8-OH-DPAT-induced oxytocin secretion. We conclude that 5-HT-induced vasopressin secretion primarily is mediated via 5-HT2C, 5-HT4 and 5-HT7 receptors, whereas 5-HT2A, 5-HT3 and 5-HT5A receptors seem to be of minor importance. 5-HT-induced oxytocin secretion involves 5-HT1A, 5-HT2C and 5-HT4 receptors; in addition an involvement of 5-HT1B, 5-HT5A and 5-HT7 receptors seems likely, whereas 5-HT2A and 5-HT3 receptors seem to be less important.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2826.2003.00978.x
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  • 5
    Electronic Resource
    Electronic Resource
    Control of Blumeria graminis f.sp. hordei by treatment with mycelial extracts from cultured fungi (2001)
    Oxford, UK : Blackwell Science Ltd
    Plant pathology 50 (2001), S. 0 
    Details
    ISSN: 1365-3059
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: High levels of protection against infection from Blumeria graminis f.sp. hordei in the susceptible barley cv. Pallas were obtained by pretreatment with mycelial extracts or culture filtrates from seven different fungi (Bipolaris oryzae, B. sorokiniana, Drechslera teres f. maculata, Fusarium culmorum, Trichoderma harzianum, Pythium ultimum and Rhizopus stolonifer). Three mycelial extracts from the taxonomically different fungi B. oryzae, P. ultimum and R. stolonifer were selected for detailed study. In general the number of colonies formed was reduced by 70–98% compared with controls. Furthermore, the few colonies that developed on treated leaves were generally smaller and showed reduced spore production. Protection was limited to the area of the leaves treated with mycelial extracts and a systemic effect could not be detected. No differences in the protection level were observed when treatment was conducted between 2 h and 3 days before inoculation. It is suggested that components in the mycelial extracts interacted directly with B. graminis and that this antifungal effect was responsible for the observed protection. However, indirect effects of the mycelial extracts mediated by locally induced resistance cannot be precluded.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-3059.2001.00595.x
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  • 6
    Electronic Resource
    Electronic Resource
    Lack of Influence of Collagen Type Iα1 Sp1 Binding Site Polymorphism on the Rate of Bone Loss in a Cohort of Postmenopausal Danish Women Followed for 18 Years (2000)
    Springer
    Calcified tissue international 66 (2000), S. 409-413 
    Details
    ISSN: 1432-0827
    Keywords: Key words: COLIA1 — Collagen — Sp1 — Polymorphism — Bone loss.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. A polymorphism in an Sp1 site in the collagen Iα1 (COLIA1) gene has recently been identified and the Ss and ss genotypes were shown to be potentially important determinants of low bone mass in postmenopausal women. Additionally, in a Dutch population, the association of the COLIA1 polymorphism with low bone mineral density (BMD) was more pronounced with increasing age, suggesting a genotype effect on the rate of bone loss. We have investigated the relationship between the COLIA1 Sp1 polymorphism and the rate of bone loss in a longitudinal study with a total of 133 postmenopausal women followed for 18 years. The frequencies of the genotypes were SS 70.7%, Ss 27.8%, ss 1.5% and were in Hardy-Weinberg equilibrium. No association of the COLIA1 genotype with rate of bone loss was detected and there was no difference between the genotype groups with respect to BMD at the femoral neck or lumbar spine. Women with the Ss or ss genotypes, who have been postulated to have low BMD, had even higher BMD at the lower forearm than women with the SS genotype. The levels of serum osteocalcin and urinary collagen type I degradation products were not found to be associated with the COLIA1 Sp1 polymorphism. In conclusion, this study does not support the hypothesis that the Ss COLIA1 genotype predisposes women to increased rate of bone loss or low BMD. However, because of a low absolute number of the ss genotype, it was not possible to reach a conclusion on this particular genotype with regard to an association with low BMD or rate of bone loss.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002230010083
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  • 7
    Electronic Resource
    Electronic Resource
    The effect of CVVHD and endotoxin on the oxidative burst, adhesion molecules and distribution in tissues of granulocytes (2000)
    Springer
    Intensive care medicine 26 (2000), S. 770-775 
    Details
    ISSN: 1432-1238
    Keywords: Key words Adhesion molecules ; CVVHD ; Endotoxin ; Granulocytes ; Oxidative burst
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objective: Extracorporeal circulation, such as cardiopulmonary bypass and haemodialysis, has been associated with an activation of the immune system, especially the granulocytes. Continuous veno-venous haemodiafiltration (CVVHD) is used in critically ill septic patients. During CVVHD cytokines are excreted in the ultrafiltrate. But when the membranes used in CVVHD are cultured with granulocytes, the granulocytes are slightly activated. This effect is potentiated by endotoxin. We therefore, in vivo, compared the effect on granulocyte activation of CVVHD with an endotoxin group and a control group.¶Methods: Thirty-one pigs were anaesthetized and mechanically ventilated. In ten pigs CVVHD was performed. Eleven pigs received an infusion of Escherichia coli endotoxin 30 μ/kg–1 and ten pigs served as a control group. The adhesion molecules CD18 and CD62L were measured using monoclonal antibodies. The oxidative burst activity was assayed as superoxide dismutase-inhibitory reduction of cytochrome c. The number of granulocytes in peripheral blood and in the lungs and liver were counted.¶Results: The infusion of endotoxin was followed by granulocytopenia, reduced oxidative burst activity, increased expression of CD18 and decreased expression of CD62L on granulocytes. Accumulation of granulocytes in liver and lung tissue was also noted in this group. CVVHD was only associated with a non-significant decrease in CD62L expression on granulocytes. It did not affect any of the other measured immunological parameters.¶Conclusion: In contrast to endotoxin-induced sepsis, the granulocytes were not activated during CVVHD.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001340051245
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