Long term exposure to dopamine reverses the inhibitory effect of endothelin-1 on prolactin secretion.

Endocrinology ◽  
1995 ◽  
Vol 136 (3) ◽  
pp. 990-994 ◽  
Author(s):  
B Kanyicska ◽  
J D Livingstone ◽  
M E Freeman
Keyword(s):  
Inhibitory Effect ◽  
Prolactin Secretion ◽  
Endothelin 1

scholarly journals Endothelial dysfunction in obstructive sleep apnea patients

2021 ◽  
Author(s):  
Michał Harańczyk ◽  
Małgorzata Konieczyńska ◽  
Wojciech Płazak
Keyword(s):  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Endothelial Dysfunction ◽  
Right Ventricular ◽  
Contractile Function ◽  
Sleep Apnea Syndrome ◽  
Apnea Hypopnea Index ◽  
Endothelin 1 ◽  
Obstructive Sleep

Abstract Purpose Obstructive sleep apnea syndrome (OSAS) is an independent risk factor for cardiovascular diseases. The aim of the study was to assess the influence of OSAS on endothelial dysfunction and thrombosis biomarkers and to evaluate the effect of treatment with continuous positive airway pressure (CPAP) on biomarker levels. Methods NT-proBNP, sICAM-1, endothelin-1, von Willebrand factor, D-dimers, and thrombin-antithrombin complex (TAT) were measured in 50 patients diagnosed with moderate-to-severe OSAS. All patients underwent transthoracic echocardiography, and 38 months after the inclusion, 16 CPAP users and 22 non-CPAP users were reassessed. Results Sleep-related indices of apnea-hypopnea index (AHI) and mean SpO2 were associated with higher sICAM-1 levels (AHI < 30: 7.3 ± 4.7 vs. AHI ≥ 30: 19.5 ± 19.4 mg/ml, p = 0.04; SpO2 ≥ 90%: 11.9 ± 9.3 vs. SpO2 < 90%: 23.6 ± 25.8, p = 0.04). sICAM-1 levels were significantly higher in obese patients, particularly with BMI ≥ 40. Plasma levels of TAT were significantly correlated with the increased right ventricular size (right ventricular diameter ≤ 37 mm: 0.86 ± 0.70 vs. > 37 mm: 1.96 ± 1.20 ng/ml, p = 0.04). Endothelin-1 levels were higher in patients with decreased right ventricular function (right ventricle TDI-derived S′ ≥ 12 cm/s: 11.5 ± 10.9 vs. < 12 cm/s: 26.0 ± 13.2 pg/ml, p = 0.04). An increase in NT-proBNP was related to impaired parameters of the right ventricular contractile function. There were no correlations between long-term CPAP therapy and the levels of biomarkers. Conclusion Severe OSAS influences endothelial damage as manifested by an increase in sICAM-1 levels. Changes in right ventricular structure and function, observed mainly in patients with higher TAT and endothelin-1 levels, are also manifested by an increase in NT-proBNP levels. Long-term CPAP treatment does not seem to influence biomarkers in patients with moderate-to-severe OSAS, which may help to explain the lack of influence of CPAP on cardiovascular risk reduction.

Effect of Anticonvulsants on the Uptake of 5-Methyltetrahydrofolic Acid by the Choroid Plexus in Rabbits

1977 ◽  
Vol 53 (1) ◽  
pp. 75-80
Author(s):  
H. Taguchi ◽  
Z. Abdul-Cader ◽  
J. Perry ◽  
E. H. Reynolds ◽  
I. Chanarin
Keyword(s):  
Folic Acid ◽  
Low Temperature ◽  
Choroid Plexus ◽  
Incubation Medium ◽  
Pernicious Anaemia ◽  
Inhibitory Effect ◽  
Anaerobic Conditions ◽  
Acid Therapy ◽  
Pteroylglutamic Acid

1. The isolated choroid plexus of the rabbit takes up 5-methyltetrahydrofolate from the incubation medium. 2. Other folate analogues (pteroylglutamic acid, methotrexate, 5-formyltetrahydrofolate = folinic acid) inhibited the uptake of 5-methyltetrahydrofolate. 3. The uptake of 5-methyltetrahydrofolate was inhibited by low temperature, anaerobic conditions and dinitrophenol. 4. The anticonvulsant drugs, diphenylhydantoin and phenobarbital, had no effect on 5-methyltetrahydrofolate uptake. 5. The inhibitory effect of pteroylglutamic acid on the uptake of 5-methyltetrahydrofolate by the choroid plexus may explain the effect of long-term folic acid therapy in aggravating vitamin B12 neuropathy in pernicious anaemia.

Influence of N-methyl-d-aspartate on the reproductive axis of male Syrian hamsters

1993 ◽  
Vol 137 (2) ◽  
pp. 247-NP ◽  
Author(s):  
H. F. Urbanski ◽  
M. M. Fahy ◽  
P. M. Collins
Keyword(s):  
Hormone Secretion ◽  
Serum Testosterone ◽  
Inhibitory Effect ◽  
Stimulatory Action ◽  
Syrian Hamsters ◽  
Reproductive Axis ◽  
Treatment Paradigm ◽  
Testicular Size ◽  
Lh Releasing Hormone

ABSTRACT The influence of excitatory amino acids (EAAs) on reproductive neuroendocrine function was investigated in adult male Syrian hamsters of the LSH/Ss Lak strain. Before the study, the animals were maintained in a sexually regressed condition, under short days (SD) and subsequently were either transferred to long days (LD) or kept under SD, for a further 4 weeks. In the former group, photostimulation produced a predictable elevation in the hypophysial contents and serum concentrations of FSH and LH. This was accompanied by an increase in testicular size, an elevation in serum testosterone levels and an increase in spermatogenic activity; the SD hamsters remained sexually quiescent throughout the study. In contrast, SD hamsters that were given daily injections of the EAA agonist, N-methyl-d,l-aspartate (NMA: 50 mg/kg body weight, s.c.), showed stimulatory responses that were generally even more pronounced than those shown by the LD group. Surprisingly, an identical NMA treatment paradigm failed to cause a similar activation of the reproductive axis in LD hamsters that were given daily afternoon injections of melatonin (25 μg, s.c), even though the inhibitory effect of this melatonin treatment is generally regarded as being comparable with that produced by exposure to SD. Although EAAs can acutely stimulate the neurocircuitry that controls LH-releasing hormone secretion, the present findings suggest that EAAs might also exert a long-term stimulatory action by acting further upstream in the photoneuroendocrine pathway. Journal of Endocrinology (1993) 137, 247–252

Inhibitory effect of ipriflavone on osteoclast-mediated bone resorption and new osteoclast formation in long-term cultures of mouse unfractionated bone cells

1993 ◽  
Vol 53 (3) ◽  
pp. 206-209 ◽  
Author(s):  
Kohei Notoya ◽  
Keiji Yoshida ◽  
Shigehisa Taketomi ◽  
Iwao Yamazaki ◽  
Masayoshi Kumegawa
Keyword(s):  
Bone Resorption ◽  
Bone Cells ◽  
Inhibitory Effect ◽  
Osteoclast Formation

scholarly journals The Anti-inflammatory Cytokine, Interleukin (IL)-10, Blocks the Inhibitory Effect of IL-1β on Long Term Potentiation

2001 ◽  
Vol 276 (49) ◽  
pp. 45564-45572 ◽  
Author(s):  
Áine Kelly ◽  
Aileen Lynch ◽  
Emily Vereker ◽  
Yvonne Nolan ◽  
Patrice Queenan ◽  
...  
Keyword(s):  
Inflammatory Cytokine ◽  
Long Term Potentiation ◽  
Inhibitory Effect ◽  
Term Potentiation ◽  
Anti Inflammatory ◽  
Anti Inflammatory Cytokine

scholarly journals Effects of low-dose aspirin on the osseointegration process in rats

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Ana Carolina Lupepsa ◽  
Paula Vargas-Sanchez ◽  
Marcella Goetz Moro ◽  
Leomar Emanuel Almeida Mecca ◽  
Marcela Claudino ◽  
...  
Keyword(s):  
Low Dose ◽  
Inhibitory Effect ◽  
Control Group ◽  
Implant Placement ◽  
Dose Aspirin ◽  
Low Dose Aspirin ◽  
Male Wistar Rats ◽  
Bone To Implant Contact ◽  
Bone Deposition

Abstract Background Several drugs are capable of promoting changes in bone metabolism. The aim of this study was to evaluate the effect of long-term low-dose aspirin (LDA) therapy on implant osseointegration. Methods Male Wistar rats were divided into 4 groups (n = 8/group) according to oral gavage solution received prior (42 days) to the implant surgery on the tibia. The control group was treated with saline solution for 7 (CG-7) and 28 (CG-28) days. The use of low-dose aspirin was performed in AG groups (6.75 mg/kg of aspirin) for 7 (AG-7) and 28 (AG-28) days. After experimental periods, histomorphometric evaluation of bone-to-implant contact (BIC) and the bone area between threads (BABT) was performed. Results Reduced BIC values were detected in AG-7 (62.8% ± 17.1) group compared to AG-28 (91.9% ± 5.4), CG-7 (82.7% ± 15.2), and CG-28 (89.9% ± 9.7). BABT evaluation revealed lower values in AG-7 (70.9% ± 15.2) compared to AG-28 (95.4% ± 3.7) and CG-28 (87.1% ± 10.2) groups. Conclusions The treatment with low doses of aspirin promoted a discrete inhibitory effect in the early stages (7 days) of repair after implant placement, specifically in the bone deposition. However, these effects were not detected in the late stages (28 days), considering BIC and BABT parameters.

scholarly journals Changes in prolactin secretion in the short- and long-term after adrenalectomy

2012 ◽  
Vol 56 (4) ◽  
pp. 244-249 ◽  
Author(s):  
Maria Thereza C. Laguna-Abreu ◽  
Carla Germano ◽  
Ayrton C. Moreira ◽  
José Antunes-Rodrigues ◽  
Lucila Elias ◽  
...  
Keyword(s):  
Hpa Axis ◽  
Plasma Corticosterone ◽  
Prolactin Secretion ◽  
Plasma Prolactin ◽  
Peptidergic Neurons ◽  
Prolactin Release ◽  
Short And Long Term ◽  
Hypothalamus Pituitary Adrenal Axis ◽  
Pituitary Adrenal Axis

OBJECTIVE: To evaluate the modulation of the hypothalamus-pituitary-adrenal axis (HPA) on prolactin secretion in rats after adrenalectomy (ADX). MATERIALS AND METHODS: Plasma corticosterone, ACTH, and prolactin concentrations were measured by radioimmunoassay in rats after bilateral ADX in the short- (3 hours and 1day) and long-term (3, 7, and 14 days). RESULTS: Animals that underwent ADX showed undetectable corticosterone levels and a triphasic ACTH response with a transient increase (3h), a decrease (1d), and further increase in the long-term after ADX. Sham animals showed a marked increase in corticosterone and ACTH levels three hours after surgery, with a decrease to basal levels thereafter. Plasma prolactin levels were not changed after ADX. CONCLUSION: There are different points of equilibrium in the HPA axis after the glucocorticoid negative feedback is removed. Prolactin plasma secretion is not altered in the short or long- term after ADX, suggesting that the peptidergic neurons essential for prolactin release are not activated after ADX.

scholarly journals Clock genes in calendar cells as the basis of annual timekeeping in mammals--a unifying hypothesis

2003 ◽  
Vol 179 (1) ◽  
pp. 1-13 ◽  
Author(s):  
GA Lincoln ◽  
H Andersson ◽  
A Loudon
Keyword(s):  
Gene Expression ◽  
Molecular Mechanism ◽  
Clock Genes ◽  
Prolactin Secretion ◽  
Secretory Cells ◽  
Dark Phase ◽  
Pars Tuberalis ◽  
Cry Protein ◽  
Wide Range

Melatonin-based photoperiod time-measurement and circannual rhythm generation are long-term time-keeping systems used to regulate seasonal cycles in physiology and behaviour in a wide range of mammals including man. We summarise recent evidence that temporal, melatonin-controlled expression of clock genes in specific calendar cells may provide a molecular mechanism for long-term timing. The agranular secretory cells of the pars tuberalis (PT) of the pituitary gland provide a model cell-type because they express a high density of melatonin (mt1) receptors and are implicated in photoperiod/circannual regulation of prolactin secretion and the associated seasonal biological responses. Studies of seasonal breeding hamsters and sheep indicate that circadian clock gene expression in the PT is modulated by photoperiod via the melatonin signal. In the Syrian and Siberian hamster PT, the high amplitude Per1 rhythm associated with dawn is suppressed under short photoperiods, an effect that is mimicked by melatonin treatment. More extensive studies in sheep show that many clock genes (e.g. Bmal1, Clock, Per1, Per2, Cry1 and Cry2) are expressed in the PT, and their expression oscillates through the 24-h light/darkness cycle in a temporal sequence distinct from that in the hypothalamic suprachiasmatic nucleus (central circadian pacemaker). Activation of Per1 occurs in the early light phase (dawn), while activation of Cry1 occurs in the dark phase (dusk), thus photoperiod-induced changes in the relative phase of Per and Cry gene expression acting through PER/CRY protein/protein interaction provide a potential mechanism for decoding the melatonin signal and generating a long-term photoperiodic response. The current challenge is to identify other calendar cells in the central nervous system regulating long-term cycles in reproduction, body weight and other seasonal characteristics and to establish whether clock genes provide a conserved molecular mechanism for long-term timekeeping.

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