Role of Cyclic Nucleotides in Contraction Induced by Oxytocin in the Testicular Capsule of the Rat in vitro

Pharmacology ◽  
1996 ◽  
Vol 53 (5) ◽  
pp. 296-301 ◽  
Author(s):  
Manuel Sánchez ◽  
Luis Menéndez. ◽  
Maria José Garcia de Boto ◽  
Agustín Hidalgo
Keyword(s):  
Cyclic Nucleotides ◽  
Testicular Capsule

scholarly journals Oocyte maturation and quality: role of cyclic nucleotides

Reproduction ◽  
2016 ◽  
Vol 152 (5) ◽  
pp. R143-R157 ◽  
Author(s):  
R B Gilchrist ◽  
A M Luciano ◽  
D Richani ◽  
H T Zeng ◽  
X Wang ◽  
...  
Keyword(s):  
Cyclic Nucleotides ◽  
Treatment Options ◽  
Oocyte Quality ◽  
Fertility Treatment ◽  
Lower Efficiency ◽  
Oocyte Meiosis ◽  
Developmental Capacity ◽  
Oocyte Meiotic Maturation

The cyclic nucleotides, cAMP and cGMP, are the key molecules controlling mammalian oocyte meiosis. Their roles in oocyte biology have been at the forefront of oocyte research for decades, and many of the long-standing controversies in relation to the regulation of oocyte meiotic maturation are now resolved. It is now clear that the follicle prevents meiotic resumption through the actions of natriuretic peptides and cGMP – inhibiting the hydrolysis of intra-oocyte cAMP – and that the pre-ovulatory gonadotrophin surge reverses these processes. The gonadotrophin surge also leads to a transient spike in cAMP in the somatic compartment of the follicle. Research over the past two decades has conclusively demonstrated that this surge in cAMP is important for the subsequent developmental capacity of the oocyte. This is important, as oocyte in vitro maturation (IVM) systems practised clinically do not recapitulate this cAMP surge in vitro, possibly accounting for the lower efficiency of IVM compared with clinical IVF. This review particularly focuses on this latter aspect – the role of cAMP/cGMP in the regulation of oocyte quality. We conclude that clinical practice of IVM should reflect this new understanding of the role of cyclic nucleotides, thereby creating a new generation of ART and fertility treatment options.

CGRP and ANF cause relaxation of opossum internal anal sphincter via different mechanisms

1991 ◽  
Vol 260 (5) ◽  
pp. G764-G769 ◽  
Author(s):  
S. Rattan ◽  
C. Moummi ◽  
S. Chakder
Keyword(s):  
Smooth Muscle ◽  
Anal Sphincter ◽  
Cyclic Nucleotides ◽  
Internal Anal Sphincter ◽  
Camp Content ◽  
Calcitonin Gene ◽  
Before And After ◽  
Camp And Cgmp

This investigation examined and compared the role of cyclic nucleotides in the mediation of internal anal sphincter (IAS) relaxation caused by the addition of neuropeptide calcitonin gene-related peptide (CGRP) and atrial natriuretic factor (ANF). The studies were performed in vitro on smooth muscle strips of opossum IAS. The relaxation produced by CGRP and ANF was examined before and after the addition of tetrodotoxin (TTX) (1 x 10(-6)M). At this concentration, TTX did not have any significant effect on the relaxation produced by either CGRP or ANF, suggesting that these peptides act directly on the smooth muscle. Addition of CGRP (3 x 10(-6) M) produced the maximal relaxation and significantly increased cAMP content without changing cGMP. On the other hand, addition of ANF (3 x 10(-6) M) caused a similar fall in IAS tension that was accompanied by a significant elevation in cGMP without any change in cAMP content. The rises in the levels of cyclic nucleotides preceded the onset of fall in the resting tension of IAS. Our results demonstrate that CGRP and ANF relax isolated strips of opossum IAS by their action directly at the smooth muscle and that this relaxation is associated with an increase in cAMP and cGMP, respectively. The studies suggest the presence of both cAMP and cGMP pathways in the IAS and that the relaxation of IAS smooth muscle in response to different peptides may occur via a specific intracellular biochemical pathway.

scholarly journals Role of microtubules in granulocyte adherence

Blood ◽  
1978 ◽  
Vol 51 (6) ◽  
pp. 1045-1050
Author(s):  
LA Boxer ◽  
JM Allen ◽  
AM Watanabe ◽  
HR Jr Besch ◽  
RL Baehner
Keyword(s):  
Ascorbic Acid ◽  
Cyclic Nucleotides ◽  
Polymorphonuclear Leukocytes ◽  
Microtubule Assembly ◽  
Dose Dependent Fashion ◽  
Chediak Higashi Syndrome ◽  
Human Polymorphonuclear Leukocytes ◽  
Dose Dependent

The adherence of human polymorphonuclear leukocytes (PMN) to nylon fibers is inhibited in a dose-dependent fashion by exposure in vitro of these cells to either colchicine or VM-26, both of which agents prevent microtubule assembly. Mean adherence of human PMN was 48% +/- 2%, following treatment with 10(-5) M colchicine or 10(-4) M VM-26 it was reduced to 31% +/- 2% and 7%, respectively. Peritoneal PMN obtained from mice and mink with Chediak-Higashi syndrome (CHS) thought to have a microtubule-membrane disorder affecting the PMN had a mean adherence of 29% +/- 3% and 40% +/- 8% compared to control values of 46% +/- 5% and 73% +/- 8%, respectively, from the mice and mink. Both ascorbic acid and bethanechol, shown previously to enhance microtubule assembly in humans with CHS, normalized granulocyte adherence in PMN obtained from mice with CHS. Cyclic nucleotide levels were not altered by treatment of human PMN with colchicine, nor did they differ between normal and CHS animals. Thus it appears that the state of microtubule assembly may directly affect the properties of the PMN plasma membrane without requiring alterations of cyclic nucleotides as an intermediary.

scholarly journals Role of microtubules in granulocyte adherence

Blood ◽  
1978 ◽  
Vol 51 (6) ◽  
pp. 1045-1050 ◽  
Author(s):  
LA Boxer ◽  
JM Allen ◽  
AM Watanabe ◽  
HR Jr Besch ◽  
RL Baehner
Keyword(s):  
Ascorbic Acid ◽  
Cyclic Nucleotides ◽  
Polymorphonuclear Leukocytes ◽  
Microtubule Assembly ◽  
Dose Dependent Fashion ◽  
Chediak Higashi Syndrome ◽  
Human Polymorphonuclear Leukocytes ◽  
Dose Dependent

Abstract The adherence of human polymorphonuclear leukocytes (PMN) to nylon fibers is inhibited in a dose-dependent fashion by exposure in vitro of these cells to either colchicine or VM-26, both of which agents prevent microtubule assembly. Mean adherence of human PMN was 48% +/- 2%, following treatment with 10(-5) M colchicine or 10(-4) M VM-26 it was reduced to 31% +/- 2% and 7%, respectively. Peritoneal PMN obtained from mice and mink with Chediak-Higashi syndrome (CHS) thought to have a microtubule-membrane disorder affecting the PMN had a mean adherence of 29% +/- 3% and 40% +/- 8% compared to control values of 46% +/- 5% and 73% +/- 8%, respectively, from the mice and mink. Both ascorbic acid and bethanechol, shown previously to enhance microtubule assembly in humans with CHS, normalized granulocyte adherence in PMN obtained from mice with CHS. Cyclic nucleotide levels were not altered by treatment of human PMN with colchicine, nor did they differ between normal and CHS animals. Thus it appears that the state of microtubule assembly may directly affect the properties of the PMN plasma membrane without requiring alterations of cyclic nucleotides as an intermediary.

scholarly journals The role of nitric oxide synthesis induction and inhibition in regulation of blood neutrophil cell death during oxidative disbalance

2010 ◽  
Vol 56 (5) ◽  
pp. 587-595 ◽  
Author(s):  
N.V. Ryazantseva ◽  
T.V. Zhavoronok ◽  
E.A. Stepovaya ◽  
Yu.V. Starikov ◽  
V.A. Bychkov
Keyword(s):  
Oxidative Stress ◽  
Nitric Oxide ◽  
Cell Death ◽  
Cyclic Nucleotides ◽  
Acute Inflammation ◽  
Nitric Oxide Synthesis ◽  
Blood Neutrophil ◽  
Neutrophil Cell

Modeling oxidative stress in vitro with 5мМ H2O2 has demonstrated a protective role of nitric oxide on realization of constitutional blood neutrophil cell death. The NO-synthase inductor L-arginine and the inhibitor of nitric oxide synthesis, L-NAME, influenced on the amount of annexin-positive cells, the content of Bax protein, reactive oxygen species, cyclic nucleotides, and calcium homeostasis in neutrophils under conditions realizing programmed death during oxidative stress in vitro and under acute inflammation. During oxidative stress L-arginine normalized the increased intracellular Ca2+ level and the cАМP/cGМP ratio due to increase of cGМP level, stabilized metabolism and prolonged neutrophil life. During acute inflammation NO induction was insufficient for limitation of Ca2+ release into cytosol and for onset of the apoptotic effect; blockade of NO synthesis deteriorated this situation by activating neutrophil apoptosis due to the sharp increase in Ca2+ content and reduction of cyclic nucleotides in cytosol. The protective effect of NO on neutrophil cell death during oxidative dysbalance is not associated with regulation of apoptotic protein Bax.

The role of silicon in forages: A quantitative X-Ray study

1987 ◽  
Vol 45 ◽  
pp. 416-417
Author(s):  
Janet H. Woodward ◽  
D. E. Akin
Keyword(s):  
Sodium Acetate ◽  
Dry Matter ◽  
Acetate Buffer ◽  
Plant Tissues ◽  
Sodium Acetate Buffer ◽  
X Ray ◽  
Dry Matter Digestibility ◽  
Percent Composition

Silicon (Si) is distributed throughout plant tissues, but its role in forages has not been clarified. Although Si has been suggested as an antiquality factor which limits the digestibility of structural carbohydrates, other research indicates that its presence in plants does not affect digestibility. We employed x-ray microanalysis to evaluate Si as an antiquality factor at specific sites of two cultivars of bermuda grass (Cynodon dactvlon (L.) Pers.). “Coastal” and “Tifton-78” were chosen for this study because previous work in our lab has shown that, although these two grasses are similar ultrastructurally, they differ in in vitro dry matter digestibility and in percent composition of Si.Two millimeter leaf sections of Tifton-7 8 (Tift-7 8) and Coastal (CBG) were incubated for 72 hr in 2.5% (w/v) cellulase in 0.05 M sodium acetate buffer, pH 5.0. For controls, sections were incubated in the sodium acetate buffer or were not treated.

An integrated screening method for evaluating the pulmonary toxicity of inhaled particulates: Role of microscopic techniques in assessing pulmonary macrophage clearance functions

1990 ◽  
Vol 48 (3) ◽  
pp. 826-827
Author(s):  
David B. Warheit ◽  
Lena Achinko ◽  
Mark A. Hartsky
Keyword(s):  
Bronchoalveolar Lavage ◽  
Pulmonary Toxicity ◽  
Screening Method ◽  
Pulmonary Response ◽  
Inhaled Particles ◽  
Cytochemical Analysis ◽  
Pulmonary Macrophages ◽  
Integrated Screening

There is a great need for the development of a rapid and reliable bioassay to evaluate the pulmonary toxicity of inhaled particles. A number of methods have been proposed, including lung clearance studies, bronchoalveolar lavage analysis, and in vitro cytotoxicity tests. These methods are often limited in scope inasmuch as they measure only one dimension of the pulmonary response to inhaled, instilled or incubated dusts. Accordingly, a comprehensive approach to lung toxicity studies has been developed.To validate the method, rats were exposed for 6 hours or 3 days to various concentrations of either aerosolized alpha quartz silica (Si) or carbonyl iron (CI) particles. Cells and fluids from groups of sham and dust-exposed animals were recovered by bronchoalveolar lavage (BAL). Alkaline phosphatase, LDH and protein values were measured in BAL fluids at several time points postexposure. Cells were counted and evaluated for viability, as well as differential and cytochemical analysis. In addition, pulmonary macrophages (PM) were cultured and studied for morphology, chemotaxis, and phagocytosis by scanning electron microscopy.

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