Mechanisms of the inhibitory effect of cyclic adenosine monophosphate on calcium current in intact mollusk neurons

1990 ◽  
Vol 22 (1) ◽  
pp. 45-50
Author(s):  
E. I. Solntseva
Keyword(s):  
Calcium Current ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Inhibitory Effect ◽  
Mollusk Neurons

Inhibitory effect of irradiation products of cyclic adenosine-monophosphate on the relaxing ability of smooth muscle preparations

1982 ◽  
Vol 21 (2) ◽  
pp. 97-107
Author(s):  
L. Schachinger ◽  
U. Hagen ◽  
H. Kl�ter ◽  
Ch. Schippel ◽  
M. Jaenicke
Keyword(s):  
Smooth Muscle ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Inhibitory Effect

Inhibitory action of somatostatin-14 on hormone-stimulated cyclic adenosine monophosphate induction in porcine granulosa and luteal cells

1992 ◽  
Vol 134 (2) ◽  
pp. 297-306 ◽  
Author(s):  
K. Rajkumar ◽  
D. E. Kerr ◽  
R. N. Kirkwood ◽  
B. Laarveld
Keyword(s):  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Luteal Cells ◽  
Camp Generation ◽  
Camp Induction ◽  
Camp Levels ◽  
Somatostatin 14

ABSTRACT Somatostatin-14 (SRIF-14) inhibited, in a concentration-dependent manner, LH- and forskolin-stimulated cyclic adenosine monophosphate (cAMP) induction in porcine granulosa and luteal cells. The inhibitory effect of SRIF-14 on hormone-induced cAMP generation was more potent in porcine ovarian cells than in the GH-3 pituitary cell line. The inhibitory effect of SRIF-14 was impeded by neutralizing its biological activity with specific antiserum. Preincubation of luteal and granulosa cells with phorbol 12-myristate 13-acetate (PMA) enhanced LH- and forskolin-stimulated cAMP levels. SRIF-14 failed to inhibit LH- or forskolin-stimulated cAMP levels in cells preincubated with PMA. It is concluded that SRIF-14 inhibits hormone-stimulated cAMP induction in the porcine ovary. LH-induced protein kinase C activation may be physiologically important to alleviate the inhibitory effects of SRIF-14. Journal of Endocrinology (1992) 134, 297–306

scholarly journals Adenosine and Forskolin Inhibit Platelet Aggregation by Collagen but not the Proximal Signalling Events

2019 ◽  
Vol 119 (07) ◽  
pp. 1124-1137 ◽  
Author(s):  
Joanne C. Clark ◽  
Deirdre M. Kavanagh ◽  
Stephanie Watson ◽  
Jeremy A. Pike ◽  
Robert K. Andrews ◽  
...  
Keyword(s):  
Adenylyl Cyclase ◽  
G Protein ◽  
Platelet Activation ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Adenosine Diphosphate ◽  
Receptor Activation ◽  
Inhibitory Effect ◽  
Human Platelets ◽  
Adenosine Receptor Agonist

Background The G protein-coupled receptor, adenosine A2A, signals through the stimulatory G protein, Gs, in platelets leading to activation of adenylyl cyclase and elevation of cyclic adenosine monophosphate (cAMP) and inhibition of platelet activation. Objective This article investigates the effect of A2A receptor activation on signalling by the collagen receptor glycoprotein (GP) VI in platelets. Methods Washed human platelets were stimulated by collagen or the GPVI-specific agonist collagen-related peptide (CRP) in the presence of the adenosine receptor agonist, 5′-N-ethylcarboxamidoadenosine (NECA) or the adenylyl cyclase activator, forskolin and analysed for aggregation, adenosine triphosphate secretion, protein phosphorylation, spreading, Ca2+ mobilisation, GPVI receptor clustering, cAMP, thromboxane B2 (TxB2) and P-selectin exposure. Results NECA, a bioactive adenosine analogue, partially inhibits aggregation and secretion to collagen or CRP in the absence or presence of the P2Y12 receptor antagonist, cangrelor and the cyclooxygenase inhibitor, indomethacin. The inhibitory effect in the presence of the three inhibitors is largely overcome at higher concentrations of collagen but not CRP. Neither NECA nor forskolin altered clustering of GPVI, elevation of Ca2+ or spreading of platelets on a collagen surface. Further, neither NECA nor forskolin, altered collagen-induced tyrosine phosphorylation of Syk, LAT nor PLCγ2. However, NECA and forskolin inhibited platelet activation by the TxA2 mimetic, U46619, but not the combination of adenosine diphosphate and collagen. Conclusion NECA and forskolin have no effect on the proximal signalling events by collagen. They inhibit platelet activation in a response-specific manner in part through inhibition of the feedback action of TxA2.

scholarly journals THE EFFECT OF SOME FACTORS ON THE HISTOCHEMICAL DEMONSTRATION OF LIVER GLYCOGEN PHOSPHORYLASE ACTIVITY

1972 ◽  
Vol 20 (5) ◽  
pp. 331-335 ◽  
Author(s):  
L.-A. LINDBERG ◽  
A. PALKAMA
Keyword(s):  
Enzyme Activity ◽  
Light Microscope ◽  
Ethylenediaminetetraacetic Acid ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Liver Glycogen ◽  
Inhibitory Effect ◽  
Histochemical Demonstration ◽  
Phosphorylase Activity ◽  
Glycogen Phosphorylase Activity

Existing methods for the histochemical demonstration of liver phosphorylase activity were investigated for possible application to a study of enzyme activity using the electron microscope as well as the light microscope. It was found that lead, in concentrations recommended in the literature, cannot be used as the precipitating agent because of its inhibitory effect on phosphorylase activity. The histochemical method based on the demonstration of enzymatically formed glycogen can be improved by adding ethylenediaminetetraacetic acid to the incubating solution. However, the addition of 3',5'-cyclic adenosine monophosphate is not as effective. It is not necessary to add glycogen to the incubating solution. In our opinion enzyme activity cannot yet be demonstrated electron microscopically by the precipitation of liberated phosphate. This is due to the inhibitory effect of high lead concentrations. Under the light microscope the method based on the demonstration of enzymatically formed glycogen is most reliable.

Differential Effect of Halothane and Forskolin on Platelet Cytosolic Ca (2+) Mobilization and Aggregation 

1998 ◽  
Vol 89 (2) ◽  
pp. 401-410 ◽  
Author(s):  
Francois Corbin ◽  
Gilbert Blaise ◽  
Remy Sauve
Keyword(s):  
Platelet Aggregation ◽  
Platelet Activating Factor ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Inhibitory Effect ◽  
Signaling Cascade ◽  
Aggregation Process ◽  
Camp Production ◽  
Biochemical Pathways ◽  
Stimulation Of

Background Previous works have suggested that the impairment of platelet aggregation by halothane was partly related to a stimulation of cyclic adenosine monophosphate (cAMP) production, to an inhibitory effect on Ca2+ signaling, or both. Intracellular Ca2+ measurements therefore were undertaken, first to determine the critical steps in the platelet CaZ+ signaling cascade most likely to be affected by halothane or by an increase in cAMP production, and second to establish if the effect of halothane involves aggregation-related biochemical pathways triggered by an increase in internal Ca2+. Methods Human washed platelets were treated with halothane or forskolin for 5 min before application of either platelet-activating factor, thrombin, U46619, or thapsigargin. The cytosolic Ca2+ concentration ([Ca2+]i) was measured with the fluorescent Ca2+ indicator fura-2. Nephelometric measurements were also performed to assay the aggregation process. Results Our results indicate that pretreating platelets with halothane leads to a partial impairment of the [Ca2+]i increase induced either by U46619, thrombin, or platelet-activating factor, but this had no significant effect on the [Ca2+]i response triggered by thapsigargin. In addition, our results show that halothane inhibits platelet aggregation triggered by U46619, but not by thapsigargin. Conversely, forskolin completely inhibited the [Ca2+]i response to U46619 and thapsigargin and prevented platelet aggregation induced by both agonists. Conclusions These results suggest that halothane and cAMP exert their effects on platelet aggregation and Ca2+ signaling through different mechanisms, and that halothane cannot impair platelet aggregation independently of phospholipase C stimulation.

Effects of oestradiol and prolactin on progesterone production by rhesus monkey luteal cells in vitro

1985 ◽  
Vol 108 (2) ◽  
pp. 266-272 ◽  
Author(s):  
Richard F. Laherty ◽  
Daniel Rotten ◽  
May Yamamoto ◽  
Robert B. Jaffe
Keyword(s):  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Inhibitory Effect ◽  
Corpora Lutea ◽  
Experimental Conditions ◽  
Luteal Cells ◽  
Progesterone Production ◽  
Mechanical Disruption ◽  
Progesterone Secretion

Abstract. The effects of oestradiol and prolactin (Prl) on progesterone production by dispersed monkey luteal cells were examined. Corpora lutea were recovered from monkeys 5–7 days following ovulation induction during the puerperium. The tissue was dispersed by collagenase and mechanical disruption. The resulting cells were incubated in Dulbecco's modified Eagle's medium, containing the hormones to be tested, for 3 h at 37°C. The medium was removed and assayed for progesterone by RIA. Human luteinizing hormone (hLH) produced a significant, dose-related increase in progesterone secretion that was comparable to that produced by dibutyryl cyclic adenosine monophosphate. Human follicle stimulating hormone (hFSH) had no effect upon progesterone production by the luteal cells. Oestradiol (100–10 000 pg/ml) produced a significant, dose-related decrease in both basal and hLH-stimulated progesterone production. Ovine Prl (oPrl) had neither a stimulatory nor an inhibitory effect upon basal progesterone secretion at doses up to 1000 ng/ml. Further, oPrl did not affect hLH-stimulated progesterone production. We conclude that oestradiol is a potent inhibitor of luteal progesterone secretion in vitro and that Prl does not inhibit progesterone production in the primate corpus luteum under these experimental conditions.

scholarly journals Development of a Rapid Mass Spectrometric Determination of AMP and Cyclic AMP for PDE3 Activity Study: Application and Computational Analysis for Evaluating the Effect of a Novel 2-oxo-1,2-dihydropyridine-3-carbonitrile Derivative as PDE-3 Inhibitor

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1817 ◽  
Author(s):  
Ilaria Cicalini ◽  
Barbara De Filippis ◽  
Nicola Gambacorta ◽  
Antonio Di Michele ◽  
Silvia Valentinuzzi ◽  
...  
Keyword(s):  
Phosphodiesterase Inhibitor ◽  
Parent Drug ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Binding Mode ◽  
Inhibitory Effect ◽  
Docking Studies ◽  
Mass Spectrometric ◽  
Inhibitory Potential

A simple, quick, easy and cheap tandem mass spectrometry (MS/MS) method for the determination of adenosine monophosphate (AMP) and cyclic adenosine monophosphate (cAMP) has been newly developed. This novel MS/MS method was applied for the evaluation of the inhibitory effect of a novel 2-oxo-1,2-dihydropyridine-3-carbonitrile derivative, also named DF492, on PDE3 enzyme activity in comparison to its parent drug milrinone. Molecule DF492, with an IC50 of 409.5 nM, showed an inhibition of PDE3 greater than milrinone (IC50 = 703.1 nM). To explain the inhibitory potential of DF492, molecular docking studies toward the human PDE3A were carried out with the aim of predicting the binding mode of DF492. The presence of different bulkier decorating fragments in DF492 was pursued to shift affinity of this novel molecule toward PDE3A compared to milrinone in accordance with both the theoretical and experimental results. The described mass spectrometric approach could have a wider potential use in kinetic and biomedical studies and could be applied for the determination of other phosphodiesterase inhibitor molecules.

Effect of dopamine on adenylate cyclase activity, polyphosphoinositide metabolism and cytosolic calcium concentrations in frog pituitary melanotrophs

1993 ◽  
Vol 136 (3) ◽  
pp. 421-429 ◽  
Author(s):  
L. Desrues ◽  
M. Lamacz ◽  
B. G. Jenks ◽  
H. Vaudry ◽  
M. C. Tonon
Keyword(s):  
Calcium Channels ◽  
Inositol Trisphosphate ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Cytosolic Calcium ◽  
Inhibitory Effect ◽  
Intermediate Lobe ◽  
Camp Production ◽  
Membrane Phospholipids ◽  
Voltage Dependent

ABSTRACT It has previously been shown that dopamine plays a pivotal role in the regulation of α-melanocyte-stimulating hormone (α-MSH) secretion from the intermediate lobe of the pituitary. In the present study, we have investigated the various intracellular mechanisms that are associated with the action of dopamine on frog pituitary melanotrophs. Dopamine reduced forskolin-stimulated cyclic adenosine monophosphate (cAMP) production and the inhibitory effect of dopamine was blocked by the dopaminergic D2 receptor antagonist sulpiride. The D2 receptor agonist apomorphine inhibited incorporation of [3H]inositol into membrane phospholipids. Dopamine also inhibited the formation of inositol trisphosphate and provoked accumulation of phosphatidylinositol bisphosphate. The inhibitory effect of dopamine on inositol trisphosphate production was mimicked by D2 receptor agonists and blocked by sulpiride. Using a double-wavelength microfluorimetric approach, we found that dopamine caused a rapid and transient decrease in K+-evoked stimulation of intracellular calcium concentration. The timecourses of the responses of the various intracellular messengers indicate that blockage of voltagedependent calcium channels is the primary event associated with activation of dopamine D2 receptors, while inhibition of polyphosphoinositide breakdown, related to blockage of voltage-dependent calcium channels, and reduction of cAMP production are secondary events which may contribute to the sustained inhibitory effect of dopamine on α-MSH release. Journal of Endocrinology (1993) 136, 421–429

Sign in / Sign up

Export Citation Format

Share Document