The role of cyclic AMP in the control of elasmobranch ocular tapetum lucidum pigment granule migration

1988 ◽  
Vol 28 (12) ◽  
pp. 1277-1285 ◽  
Author(s):  
Ashley R. Heath ◽  
Heather M. Hindman
Keyword(s):  
Cyclic Amp ◽  
Pigment Granule ◽  
Tapetum Lucidum ◽  
Pigment Granule Migration

Pigment granule migration in crustacean photoreceptors requires calcium

1996 ◽  
Vol 13 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Christina King-Smith ◽  
Thomas W. Cronin
Keyword(s):  
Pigment Granule ◽  
Size And Shape ◽  
Pigment Granules ◽  
Gradual Loss ◽  
Light Stimuli ◽  
Pigment Granule Migration ◽  
Normal Calcium

AbstractWe have investigated the role of calcium in the regulation of pigment granule migration in photoreceptors of the semi-terrestrial crab, Sesarma cinereum. Isolated crab eyes (eyecup plus eyestalk) were maintained in crustacean Ringer either prepared normally or calcium-free plus 50 mM EGTA. Pigment granule movement was indirectly observed by monitoring reflectance from the eye during light stimuli using intracellular optical physiological techniques. Electroretinograms (ERGs) were also measured during light stimuli. EGTA treatment caused gradual loss of centripetal migration of pigment granules (normally leading to pupillary closure), and photoreceptors eventually became locked in the open-pupil, dark-adapted state despite repeated stimuli. In contrast, ERG responses continued throughout EGTA treatment, although the size and shape ofthe response was altered. Normal ERG responses and pigment granule movements returned after replacing EGTA-Ringer with normal-calcium medium. These results suggest that centripetal migration of pigment granules in crustacean photoreceptors requires calcium.

scholarly journals Role of cyclic AMP in the control of cell-specific gene expression

1993 ◽  
Vol 4 (6) ◽  
pp. 204-209 ◽  
Author(s):  
Wolfgang Schmid ◽  
Doris Nitsch ◽  
Michael Boshart ◽  
Günther Schütz
Keyword(s):  
Gene Expression ◽  
Cyclic Amp ◽  
Specific Gene ◽  
Specific Gene Expression

scholarly journals Regulation of the expression of the mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase gene. Its role in the control of ketogenesis

1992 ◽  
Vol 283 (1) ◽  
pp. 261-264 ◽  
Author(s):  
N Casals ◽  
N Roca ◽  
M Guerrero ◽  
G Gil-Gómez ◽  
J Ayté ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Rat Liver ◽  
Genetic Expression ◽  
Fat Feeding

We have explored the role of mitochondrial 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) synthase in regulating ketogenesis. We had previously cloned the cDNA for mitochondrial HMG-CoA synthase and have now studied the regulation in vivo of the expression of this gene in rat liver. The amount of processed mitochondrial HMG-CoA synthase mRNA is rapidly changed in response to cyclic AMP, insulin, dexamethasone and refeeding, and is greatly increased by starvation, fat feeding and diabetes. We conclude that one point of ketogenic control is exercised at the level of genetic expression of mitochondrial HMG-CoA synthase.

scholarly journals Heterologous desensitization of the cyclic AMP-independent glycogenolytic response in rat liver cells

1981 ◽  
Vol 200 (3) ◽  
pp. 509-514 ◽  
Author(s):  
B Bréant ◽  
S Keppens ◽  
H De Wulf
Keyword(s):  
Cyclic Amp ◽  
Glycogen Phosphorylase ◽  
Liver Glycogen ◽  
Receptor Interaction ◽  
Alpha Adrenergic Receptors ◽  
Rat Liver Cells ◽  
Heterologous Desensitization ◽  
Highly Correlated ◽  
Alpha Agonist

Vasopressin and alpha-adrenergic agonists are known to be potent cyclic AMP-independent Ca2+-dependent activators of liver glycogen phosphorylase. When hepatocytes are pre-incubated with increasing concentrations of vasopressin or of the alpha-agonist phenylephrine, they become progressively unresponsive to a second addition of the respective agonist. The relative abilities of six vasopressin analogues and of five alpha-agonists to activate glycogen phosphorylase and to cause subsequent desensitization are highly correlated, indicating that the same vasopressin and alpha-adrenergic receptors are involved in both responses. About 5-times-higher peptide concentrations are needed to desensitize the cells than to activate their glycogen phosphorylase, whereas the concentrations of alpha-agonists required for the desensitization are only twice those needed for the activation of phosphorylase. The desensitization is not mediated by a perturbation in the agonist-receptor interaction. It is clearly heterologous, i.e. it is not agonist-specific, and must therefore involve a mechanism common to both series of agonists. The evidence for a role of Ca2+ movements or phosphatidylinositol turnover is briefly discussed.

The role of cyclic AMP in canine secretin-stimulated bile flow

1979 ◽  
Vol 27 (1) ◽  
pp. 57-61 ◽  
Author(s):  
D.L. Kaminski ◽  
M.J. Ruwart ◽  
Y.G. Deshpande
Keyword(s):  
Cyclic Amp ◽  
Bile Flow
Sign in / Sign up

Export Citation Format

Share Document