scholarly journals Stimulation of human foreskin fibroblast adenosine 3‘:5‘-cyclic monophosphate levels by prostacyclin (prostaglandin I2).

1979 ◽  
Vol 254 (5) ◽  
pp. 1671-1676 ◽  
Author(s):  
R.R. Gorman ◽  
R.D. Hamilton ◽  
N.K. Hopkins
Keyword(s):  
Human Foreskin Fibroblast ◽  
Prostaglandin I2 ◽  
Cyclic Monophosphate ◽  
Stimulation Of

Regulation of calcium mobilization and entry in human platelets by endothelium-derived factors

1994 ◽  
Vol 267 (1) ◽  
pp. C236-C244 ◽  
Author(s):  
J. Geiger ◽  
C. Nolte ◽  
U. Walter
Keyword(s):  
Endothelial Cells ◽  
Protein Kinase ◽  
Human Platelets ◽  
Dependent Protein Kinase ◽  
Rapid Phase ◽  
No Donor ◽  
Cyclic Monophosphate ◽  
Dependent Protein ◽  
Camp And Cgmp ◽  
Stimulation Of

Stimulation of Ca2+ mobilization and entry by agonists such as ADP, thrombin, and thromboxane is an early step of platelet activation. Here, we compared the effects of adenosine 3',5'-cyclic monophosphate (cAMP)-elevating prostaglandins, guanosine 3',5'-cyclic monophosphate (cGMP)-elevating nitrovasodilators, membrane-permeant selective activators of cAMP- or cGMP-dependent protein kinases, and physiological endothelium-derived factors on the agonist-evoked Ca2+ mobilization and entry in human platelets. Prostaglandin E1, the prostacyclin analogue Iloprost, the nitric oxide (NO) donor 3-morpholinosydnonimine hydrochloride, and selective activators of cGMP- or cAMP-dependent protein kinase strongly inhibited the agonist-evoked Ca2+ mobilization from intracellular stores and associated late Ca2+ entry but had little effects on the rapid (1st) phase of ADP-evoked Ca2+ entry. During coincubation of platelets with endothelial cells, endothelium-derived factors that were released strongly inhibited platelet agonist-evoked Ca2+ mobilization and only moderately affected the rapid phase of ADP-evoked Ca2+ entry. These effects were partially prevented when endothelial cells were preincubated with cyclooxygenase and/or NO synthase inhibitors. Endothelial cells therefore produce sufficient quantities of labile platelet inhibitors whose effects on the platelet Ca2+ response resemble those observed with selective cAMP- and cGMP-dependent protein kinase activators.

Stimulation of eating by the second messenger cAMP in the perifornical and lateral hypothalamus

1997 ◽  
Vol 273 (1) ◽  
pp. R107-R112 ◽  
Author(s):  
E. R. Gillard ◽  
A. M. Khan ◽  
A. ul-Haq ◽  
R. S. Grewal ◽  
B. Mouradi ◽  
...  
Keyword(s):  
Food Intake ◽  
Lateral Hypothalamus ◽  
Second Messengers ◽  
Second Messenger ◽  
Cyclic Monophosphate ◽  
Camp Analog ◽  
Complex Goal ◽  
Intracellular Action ◽  
Stimulation Of ◽  
Goal Oriented Behavior

Despite intense study of neurotransmitters mediating hypothalamic controls of food intake, little is known about which second messengers are critical for these mechanisms. To determine whether adenosine 3',5'-cyclic monophosphate (cAMP) might participate in these mechanisms, we injected the membrane-permeant cAMP analog 8-bromo-cAMP (8-BrcAMP) hypothalamically in satiated rats. Injection of 8-BrcAMP (10-100 nmol) into the perifornical (PFH) and lateral hypothalamus (LH) dose dependently stimulated food intake of up to 15.7 g in 2 h. Significantly smaller responses were obtained with thalamic injections. In contrast to the strong stimulatory effects of PFH and LH 8-BrcAMP, cAMP and 8-bromo-guanosine 3',5'-cyclic monophosphate (100 nmol) were ineffective, suggesting a chemically specific, intracellular action. Consistent with this, combined PFH injection of 7-deacetyl-7-O-(N-methylpiperazino)-tau-butyryl-forskolin dihydrochloride and 3-isobutyl-1-methylxanthine, agents that increase endogeneous cAMP, stimulated eating of up to 9.9 g in 2 h. These results demonstrate that increases in PFH/LH cAMP can elicit complex, goal-oriented behavior, suggesting an important role for cAMP in hypothalamic mechanisms stimulating food intake.

Stimulation of Ca2+ influx in αT3–1 gonadotrophs via the cAMP/PKA signaling system

1997 ◽  
Vol 273 (5) ◽  
pp. E850-E858 ◽  
Author(s):  
Marjan Hezareh ◽  
Werner Schlegel ◽  
Stephen R. Rawlings
Keyword(s):  
Adenylate Cyclase ◽  
Calcium Concentration ◽  
Cytosolic Calcium ◽  
Camp Signaling ◽  
Signaling System ◽  
Cyclic Monophosphate ◽  
Pituitary Adenylate Cyclase ◽  
Inositol 1,4,5 Trisphosphate ◽  
Made In ◽  
Stimulation Of

To investigate the regulation of free cytosolic calcium concentration ([Ca2+]i) by the adenosine 3′,5′-cyclic monophosphate (cAMP) signaling system in clonal gonadotrophs, microfluorimetric recordings were made in single indo 1-loaded αT3–1 cells. Forskolin, 8-bromoadenosine 3′,5′-cyclic monophosphate, or a low concentration (100 pM) of the hypothalamic factor pituitary adenylate cyclase-activating polypeptide (PACAP) stimulated Ca2+ step responses or repetitive Ca2+ transients, which were blocked by the removal of extracellular Ca2+ by the dihydropyridine (DHP) (+)PN 200–110 or by preincubation with the protein kinase A (PKA) antagonist H-89 (10 μM). Thus activation of the cAMP/PKA system in αT3–1 gonadotrophs stimulates Ca2+ influx through DHP-sensitive (L-type) Ca2+ channels. In contrast, high PACAP concentrations (100 nM) stimulated biphasic Ca2+ spike-plateau responses. The Ca2+ spike was independent of extracellular Ca2+, and similar responses were observed by microperfusion of individual cells withd- myo-inositol 1,4,5-trisphosphate, suggesting the involvement of the phospholipase C (PLC) signaling pathway. The Ca2+plateau depended on Ca2+ influx, was blocked by (+)PN 200–110, but was only partially blocked by H-89 pretreatment. In conclusion, PACAP stimulates [Ca2+]iincreases in αT3–1 gonadotrophs through both the PLC and adenylate cyclase signaling pathways. Furthermore, this is the first clear demonstration that the cAMP/PKA system can mediate changes in [Ca2+]iin gonadotroph-like cells.

CAP2b, a cardioacceleratory peptide, is present in Drosophila and stimulates tubule fluid secretion via cGMP

1995 ◽  
Vol 269 (6) ◽  
pp. R1321-R1326 ◽  
Author(s):  
S. A. Davies ◽  
G. R. Huesmann ◽  
S. H. Maddrell ◽  
M. J. O'Donnell ◽  
N. J. Skaer ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Manduca Sexta ◽  
High Performance ◽  
Fluid Secretion ◽  
Malpighian Tubules ◽  
Cyclic Monophosphate ◽  
Cgmp Signaling ◽  
Camp And Cgmp ◽  
Tubule Fluid ◽  
Stimulation Of

A cardioacceleratory peptide, CAP2b, identified originally in the lepidopteran Manduca sexta, stimulates fluid secretion by Malpighian tubules of the dipteran Drosophila melanogaster. High-performance liquid chromatography analyses of adult D. melanogaster reveal the presence of a CAP2b-like peptide, that coelutes with M. sexta CAP2b and synthetic CAP2b and that has CAP2b-like effects on the M. sexta heart. CAP2b accelerates fluid secretion in tubules stimulated by adenosine 3',5'-cyclic monophosphate (cAMP) but has no effect on tubules stimulated by guanosine 3',5'-cyclic monophosphate (cGMP), implying that it acts through the latter pathway. By contrast, the action of leucokinin is additive to both cAMP and cGMP but not to thapsigargin, suggesting that leucokinin acts by the elevation of intracellular calcium. CAP2b stimulation elevates tubule cGMP levels but not those of cAMP. By contrast, leucokinin has no effect on levels of either cyclic nucleotide. Both CAP2b and cGMP increase transepithelial potential difference, suggesting that stimulation of vacuolar-adenosinetriphosphatase action underlies the corresponding increases in fluid secretion. Overall, the results show that a Drosophila CAP2b-related peptide acts to stimulate fluid secretion by Malpighian tubules through the cGMP-signaling pathway.

Mechanisms of synergism between glucose and cAMP on stimulation of insulin release

1984 ◽  
Vol 247 (6) ◽  
pp. E701-E708 ◽  
Author(s):  
W. Phang ◽  
L. Domboski ◽  
Y. Krausz ◽  
G. W. Sharp
Keyword(s):  
Pancreatic Islets ◽  
Insulin Release ◽  
Ringer Solution ◽  
Intracellular Camp ◽  
Cyclic Monophosphate ◽  
Rat Pancreatic Islets ◽  
Individual Effects ◽  
The Individual ◽  
Isolated Rat ◽  
Stimulation Of

The mechanism of synergism between glucose and adenosine 3',5'-cyclic monophosphate (cAMP) on insulin release has been studied. Synergism may result from 1) inhibition of Na+-Ca2+ exchange by glucose and 2) a cAMP-induced sensitization of the release machinery to Ca2+. To distinguish between these two possibilities, isolated rat pancreatic islets were perifused with agents that raise intracellular levels of cAMP [3-isobutyl-1-methylxanthine (IBMX) and forskolin] and others that increase intracellular concentrations of Ca2+ either by blocking Na2+-Ca2+ exchange (ouabain and choline-Ringer solution) or by causing increased Ca2+ influx (KCl, carbachol, and 10 mM Ca2+). The results indicate that both the combination of cAMP and increased Ca2+ influx or blocked Na2-Ca2+ exchange and increased Ca2+ influx potentiated insulin release. When the relative potentiating abilities of cAMP and blocked Na2+-Ca2+ exchange were compared by determining the individual effects of IBMX and 1 mM ouabain (a concentration that causes similar inhibition of 45C2+ efflux as 16.7 mM glucose) in the presence of carbachol, cAMP was only 1.4 times more potent as a potentiating agent than blocked Na+-Ca2+ exchange. The greatest potentiation of insulin release was observed when Na+-Ca2+ exchange was blocked in the presence of increased levels of intracellular cAMP.

Modulation of beta-adrenergic receptor-stimulated lipolysis in the heart by prostaglandins

1996 ◽  
Vol 271 (3) ◽  
pp. E556-E562
Author(s):  
Y. Ruan ◽  
H. Kan ◽  
C. Cano ◽  
K. U. Malik
Keyword(s):  
Adrenergic Receptors ◽  
Adrenergic Receptor ◽  
Rabbit Heart ◽  
Receptor Activation ◽  
Prostaglandin Synthesis ◽  
Prostaglandin I2 ◽  
Beta Adrenergic Receptor ◽  
Beta Adrenergic ◽  
Endogenous Prostaglandin ◽  
Stimulation Of

The purpose of the present study was to investigate the contribution of prostaglandins to lipolysis elicited by beta-adrenergic receptor activation in the heart. We have studied the effect of prostaglandin E2 (PGE2), prostaglandin I2 (PGI2), and their precursor arachidonic acid (AA) in the presence and absence of a cyclooxygenase inhibitor, sodium meclofenamate, on glycerol output elicited by stimulation of beta-adrenergic receptors in the isolated rabbit heart with isoproterenol (ISOP). Bolus injections of ISOP (475 pmol) produced a constant increase in glycerol and 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha) output. Infusion of sodium meclofenamate (16 microM) reduced basal and attenuated ISOP-induced 6-keto-PGF1 alpha output and enhanced glycerol output. During inhibition of endogenous prostaglandin synthesis with meclofenamate, infusion of PGI2 or PGE2 (0.1-1 microM) inhibited ISOP-induced glycerol output. Infusion of AA (0.1-1 microM) increased 6-keto-PGF1 alpha and reduced glycerol output. Infusion of sodium meclofenamate abolished the effect of AA to increase 6-keto-PGF1 alpha and to decrease glycerol output. These data suggest that prostaglandins synthesized in the heart act as an inhibitory modulator of beta-adrenergic receptor-stimulated cardiac lipolysis.

Evidence against norepinephrine-stimulated efflux of mitochondrial Mg2+ from intact cardiac myocytes

1994 ◽  
Vol 266 (3) ◽  
pp. H1103-H1111 ◽  
Author(s):  
R. A. Altschuld ◽  
D. W. Jung ◽  
R. M. Phillips ◽  
P. Narayan ◽  
L. C. Castillo ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Fluorescence Microscopy ◽  
Cardiac Myocytes ◽  
Hormonal Regulation ◽  
Contractile Activity ◽  
Free Medium ◽  
Cyclic Monophosphate ◽  
Adult Rat ◽  
Isolated Mitochondria ◽  
Stimulation Of

We investigated the hypotheses that norepinephrine stimulates Mg2+ efflux from intact isolated adult rat ventricular cardiomyocytes and that adenosine 3',5'-cyclic monophosphate stimulates Mg2+ efflux from permeabilized myocytes and isolated mitochondria. Norepinephrine stimulation of Mg2+ release from cardiac myocytes was observed only when cells at approximately 20 mg protein/ml in Mg(2+)-containing buffer were diluted 50- to 60-fold into an Mg(2+)-free medium. Under these conditions, > 30% of total cellular lactic acid dehydrogenase activity was also released, indicating that a significant portion of the cells had died. In other protocols, where Mg2+ efflux from myocytes was not observed, extracellular Mg2+ removal and administration of 10 microM norepinephrine increased 45Ca2+ accumulation by cells in suspension. In single myocytes, Mg2+ removal and norepinephrine administration increased intracellular free [Ca2+] as measured by fura-2 fluorescence microscopy, and this was accompanied by vigorous spontaneous contractile activity followed by Ca2+ overload hypercontracture. With permeabilized myocytes and isolated mitochondria from a variety of sources, adenosine 3',5'-cyclic monophosphate did not stimulate Mg2+ efflux. These results suggest that recent evidence for direct hormonal regulation of myocardial Mg2+ homeostasis may need to be reevaluated.

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