![[Feedback]](/icons/banner/feedbackACT.gif){kind=icon}
![[For Subscribers]](/icons/banner/subscriberACT.gif){kind=icon}
![[Archive]](/icons/banner/archiveACT.gif){kind=icon}
![[Search]](/icons/banner/searchACT.gif){kind=icon}
![[Contents]](/icons/banner/tocACT.gif){kind=icon}
|
|
|
|
|
||
RP Rubin and MA Adolf
Department of Pharmacology & Therapeutics, State University of New York at Buffalo.
This study examined the mechanistic basis of the synergistic interaction between the cyclic AMP (cAMP) and phosphoinositide pathways in salivary amylase secretion. cAMP produced a concentration-dependent increase in Ca++ mobilization from saponin-permeabilized rat parotid acinar cells. A threshold concentration of cAMP (50 microM) significantly increased the peak Ca(++)-releasing activity of submaximal concentrations of inositol 1,4,5-trisphosphate (IP3) but did not augment the Ca++ mobilization induced by a maximal stimulating concentration of IP3 (30 microM). A maximal stimulating concentration of cAMP (500 microM) failed to modify the Ca++ releasing action of IP3. IP3-induced Ca++ release was also augmented by catalytic subunit of cAMP-dependent protein kinase. A specific protein kinase inhibitor reversed this effect. The cAMP-induced Ca++ release was blocked by ryanodine but not by heparin, by contrast with the IP3-induced Ca++ release. Thapsigargin only partially depressed the cAMP response but completely abolished the IP3 response. The amylase release elicited by fixed concentrations of Ca++ was not further enhanced by either cAMP or forskolin. Thus, unlike diacylglycerol, which decreases the Ca++ requirement for secretion by inducing activation of protein kinase C, cAMP appears to mediate salivary amylase secretion by regulating the sensitivity of parotid cells to the Ca++ mobilizing action of IP3. In addition, cAMP possesses a second action, i.e., directly eliciting Ca++ mobilization from an IP3-insensitive pool.
This article has been cited by other articles:
|
|
 |
|
  H.-V. Nguyen, A. Stuart-Tilley, S. L. Alper, and J. E. Melvin Cl-/HCO3- exchange is acetazolamide sensitive and activated by a muscarinic receptor-induced [Ca2+]i increase in salivary acinar cells Am J Physiol Gastrointest Liver Physiol, February 1, 2004; 286(2): G312 - G320. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Tanimura, A. Nezu, Y. Tojyo, and Y. Matsumoto Isoproterenol potentiates alpha -adrenergic and muscarinic receptor-mediated Ca2+ response in rat parotid cells Am J Physiol Cell Physiol, June 1, 1999; 276(6): C1282 - C1287. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Chaturvedi, H. Qi, D. Coleman, A. Rodriguez, P. I. Hanson, B. Striepen, D. S. Roos, and K. A. Joiner Constitutive Calcium-independent Release of Toxoplasma gondii Dense Granules Occurs through the NSF/SNAP/SNARE/Rab Machinery J. Biol. Chem., January 22, 1999; 274(4): 2424 - 2431. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Tertyshnikova and A. Fein Inhibition of inositol 1,4,5-trisphosphate-induced Ca2+ release by cAMP-dependent protein kinase in a living cell PNAS, February 17, 1998; 95(4): 1613 - 1617. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
X. Zhang, J. Wen, K. R. Bidasee, H. R. Besch Jr., and R. P. Rubin Ryanodine receptor expression is associated with intracellular Ca2+ release in rat parotid acinar cells Am J Physiol Cell Physiol, October 1, 1997; 273(4): C1306 - C1314. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. R. Giovannucci, G. E. Groblewski, J. Sneyd, and D. I. Yule Targeted Phosphorylation of Inositol 1,4,5-Trisphosphate Receptors Selectively Inhibits Localized Ca2+ Release and Shapes Oscillatory Ca2+ Signals J. Biol. Chem., October 20, 2000; 275(43): 33704 - 33711. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. I. E. Bruce, T. J. Shuttleworth, D. R. Giovannucci, and D. I. Yule Phosphorylation of Inositol 1,4,5-Trisphosphate Receptors in Parotid Acinar Cells. A MECHANISM FOR THE SYNERGISTIC EFFECTS OF cAMP ON Ca2+ SIGNALING J. Biol. Chem., January 4, 2002; 277(2): 1340 - 1348. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. V. Leaver and P. A. Pappone beta -Adrenergic potentiation of endoplasmic reticulum Ca2+ release in brown fat cells Am J Physiol Cell Physiol, May 1, 2002; 282(5): C1016 - C1024. [Abstract] [Full Text] [PDF]
|
|
 |
 |
 |
|
 |
 |
 |
