Upregulation of the adenylyl cyclase/cAMP signaling pathway in aorta from interleukin‐6 (IL‐6) knockout mice.

Cyclic AMP signals encode information required to differentially regulate a wide variety of cellular responses; yet it is not well understood how information is encrypted within these signals. An emerging concept is that compartmentalization underlies specificity within the cAMP signaling pathway. This concept is based on a series of observations indicating that cAMP levels are distinct in different regions of the cell. One such observation is that cAMP production at the plasma membrane increases pulmonary microvascular endothelial barrier integrity, whereas cAMP production in the cytosol disrupts barrier integrity. To better understand how cAMP signals might be compartmentalized, we have developed mathematical models in which cellular geometry as well as total adenylyl cyclase and phosphodiesterase activities were constrained to approximate values measured in pulmonary microvascular endothelial cells. These simulations suggest that the subcellular localizations of adenylyl cyclase and phosphodiesterase activities are by themselves insufficient to generate physiologically relevant cAMP gradients. Thus, the assembly of adenylyl cyclase, phosphodiesterase, and protein kinase A onto protein scaffolds is by itself unlikely to ensure signal specificity. Rather, our simulations suggest that reductions in the effective cAMP diffusion coefficient may facilitate the formation of substantial cAMP gradients. We conclude that reductions in the effective rate of cAMP diffusion due to buffers, structural impediments, and local changes in viscosity greatly facilitate the ability of signaling complexes to impart specificity within the cAMP signaling pathway.

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Novel Role of Brain Stem Pedunculopontine Tegmental Adenylyl Cyclase in the Regulation of Spontaneous REM Sleep in the Freely Moving Rat

Journal of Neurophysiology ◽

10.1152/jn.00272.2005 ◽

2005 ◽

Vol 94 (3) ◽

pp. 1928-1937 ◽

Cited By ~ 11

Author(s):

Subimal Datta ◽

Sarah L. Prutzman

Keyword(s):

Adenylyl Cyclase ◽

Signaling Pathway ◽

Rem Sleep ◽

Slow Wave Sleep ◽

Kainate Receptors ◽

Camp Signaling ◽

Dependent Manner ◽

Camp Signaling Pathway ◽

Freely Moving ◽

Different Doses

Physiological activation of kainate receptors and GABAB receptors within the pedunculopontine tegmentum (PPT) is involved in regulation of rapid-eye-movement (REM) sleep. Because these two types of receptors may also directly and/or indirectly activate the intracellular cyclic adenosine monophosphate (cAMP) signaling pathway, we hypothesized that this signaling pathway may be involved in the PPT to regulate spontaneous REM sleep. To test this hypothesis, four different doses (0.25, 0.50, 0.75, and 1.0 nmol) of a specific adenylyl cyclase (AC) inhibitor, 9-(tetrahydro-2-furanyl)-9H-purin-6-amine (SQ22536), were microinjected bilaterally (100 nl/site) into the PPT, and the effects on REM sleep in freely moving chronically instrumented rats were quantified. By comparing alterations in the patterns of REM sleep after control injections of vehicle or one of the four different doses of SQ22536, the contributions made by each dose of SQ22536 to REM sleep were evaluated. The results demonstrated that the local microinjection of AC inhibitor SQ22536 into the PPT decreased the total amount of REM sleep for 3 h and increased slow-wave sleep (SWS) for 2 h in a dose-dependent manner. This reduction in REM sleep was due to increased latency and decreased frequency of REM sleep episodes. These results provide evidence that inhibition of AC within the PPT can successfully reduce REM sleep. These findings suggest that activation of the cAMP-signaling pathway within the cholinergic cell compartment of the PPT is an intracellular biochemical/molecular step for generating REM sleep in the freely moving rat.

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cAMP-signaling pathway acts in selective synergism with glucose or tolbutamide to increase cytosolic Ca2+ in rat pancreatic beta-cells

Diabetes ◽

10.2337/diabetes.45.3.295 ◽

1996 ◽

Vol 45 (3) ◽

pp. 295-301 ◽

Cited By ~ 8

Author(s):

K. Yaekura ◽

M. Kakei ◽

T. Yada

Keyword(s):

Signaling Pathway ◽

Beta Cells ◽

Pancreatic Beta Cells ◽

Camp Signaling ◽

Camp Signaling Pathway

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Role of cAMP in Double Switch of Glucagon Secretion

Cells ◽

10.3390/cells10040896 ◽

2021 ◽

Vol 10 (4) ◽

pp. 896

Author(s):

Jan Zmazek ◽

Vladimir Grubelnik ◽

Rene Markovič ◽

Marko Marhl

Keyword(s):

Glucose Metabolism ◽

Signaling Pathway ◽

Cell Model ◽

Dominant Role ◽

Glucagon Secretion ◽

Camp Signaling ◽

Independent Manner ◽

Metabolic Switch ◽

Camp Signaling Pathway ◽

Double Switch

Glucose metabolism plays a crucial role in modulating glucagon secretion in pancreatic alpha cells. However, the downstream effects of glucose metabolism and the activated signaling pathways influencing glucagon granule exocytosis are still obscure. We developed a computational alpha cell model, implementing metabolic pathways of glucose and free fatty acids (FFA) catabolism and an intrinsically activated cAMP signaling pathway. According to the model predictions, increased catabolic activity is able to suppress the cAMP signaling pathway, reducing exocytosis in a Ca2+-dependent and Ca2+ independent manner. The effect is synergistic to the pathway involving ATP-dependent closure of KATP channels and consequent reduction of Ca2+. We analyze the contribution of each pathway to glucagon secretion and show that both play decisive roles, providing a kind of “secure double switch”. The cAMP-driven signaling switch plays a dominant role, while the ATP-driven metabolic switch is less favored. The ratio is approximately 60:40, according to the most recent experimental evidence.

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