Role of cyclic nucleotides in heart metabolism

1982 ◽  
Vol 16 (9) ◽  
pp. 483-507 ◽  
Author(s):  
L. H OPIE
Keyword(s):  
Cyclic Nucleotides ◽  
Heart Metabolism

Role of cyclic nucleotides in the mechanism of action of enkephalins

1982 ◽  
Vol 93 (3) ◽  
pp. 265-267
Author(s):  
M. Ya. Maizelis ◽  
A. L. Zabludovskii ◽  
S. N. Shikhov
Keyword(s):  
Mechanism Of Action ◽  
Cyclic Nucleotides

scholarly journals Phosphodiesterase Activities in the Eye of Old and Young Rats in Normoxic, Hypoxic and Hyperoxic Atmospheres

2003 ◽  
Vol 1 (1) ◽  
pp. 25-32 ◽  
Author(s):  
G. Spoto ◽  
A. Contento ◽  
M. Di Nicola ◽  
G. Bianchi ◽  
C. Di Giulio ◽  
...  
Keyword(s):  
Cyclic Nucleotides ◽  
Biological Effects ◽  
Atmospheric Oxygen ◽  
Second Messengers ◽  
Camp Phosphodiesterase ◽  
Young Rats ◽  
Physiological Processes ◽  
Adaptive Processes ◽  
Old Rats

Phosphodiesterase activity was tested on homogenized eyes of young and old rats kept in hypoxic and hyperoxic conditions, with the aim of correlating any difference in PDE activity with aging and variations in atmospheric oxygen contents. The activities of the two enzymes, cAMP phosphodiesterase (cAMP-PDE) and cGMP phosphodiesterase (cGMP-PDE), were tested. Phosphodiesterases seem to be particularly susceptible to variations in oxygen tension, suggesting an important role of cyclic nucleotides in cellular adaptive processes. Particularly, cAMP-PDE activity increases lightly both in hypoxic and hyperoxic conditions in young and old rats. For cGMP-PDE activity of young rats, a similar behaviour to cAMP-PDE activity is observed with a similar increase in hypoxic and hyperoxic conditions respect to the control rats. Instead old rats seem to be quite insensible to hypoxia, while they show a fair increase in cGMP-PDE activity in the case of hyperoxia. The second messengers cAMP and cGMP play important roles in mediating the biological effects of a wide variety of first messengers. The intracellular levels of cyclic nucleotides depend upon rates of synthesis and degradation, actuated, respectively, by cyclases and phosphodiesterases (PDEs). Therefore, PDEs seem to play an important role in a wide variety of physiological processes.

scholarly journals Effect of time and vascular pressure on permeability and cyclic nucleotides in ischemic lungs

2000 ◽  
Vol 279 (5) ◽  
pp. H2077-H2084 ◽  
Author(s):  
David B. Pearse ◽  
Patrice M. Becker
Keyword(s):  
Nitric Oxide ◽  
High Pressure ◽  
Reflection Coefficient ◽  
Cyclic Nucleotides ◽  
Fluid Flux ◽  
No Donor ◽  
Independent Mechanism ◽  
Dependent Mechanism ◽  
Intravascular Pressure

We previously found that increased intravascular pressure decreased ischemic lung injury by a nitric oxide (NO)-dependent mechanism (Becker PM, Buchanan W, and Sylvester JT. J Appl Physiol 84: 803–808, 1998). To determine the role of cyclic nucleotides in this response, we measured the reflection coefficient for albumin (ςalb), fluid flux ( J˙), cGMP, and cAMP in ferret lungs subjected to either 45 min (“short”; n = 7) or 180 min (“long”) of ventilated ischemia. Long ischemic lungs had “low” (1–2 mmHg, n = 8) or “high” (7–8 mmHg, n = 6) vascular pressure. Other long low lungs were treated with the NO donor ( Z)-1-[ N-(3-ammoniopropyl)- N-( n-propyl)amino]diazen-1-ium-1,2-diolate (PAPA-NONOate; 5 × 10−4 M, n = 6) or 8-bromo-cGMP (5 × 10−4 M, n = 6). Compared with short ischemia, long low ischemia decreased ςalb (0.23 ± 0.04 vs. 0.73 ± 0.08; P < 0.05) and increased J˙ (1.93 ± 0.26 vs. 0.58 ± 0.22 ml · min−1 · 100 g−1; P < 0.05). High pressure prevented these changes. Lung cGMP decreased by 66% in long compared with short ischemia. Lung cAMP did not change. PAPA-NONOate and 8-bromo-cGMP increased lung cGMP, but only 8-bromo-cGMP decreased permeability. These results suggest that ischemic vascular injury was, in part, mediated by a decrease in cGMP. Increased vascular pressure prevented injury by a cGMP-independent mechanism that could not be mimicked by administration of exogenous NO.

Role of Cyclic Nucleotides in Contraction Induced by Oxytocin in the Testicular Capsule of the Rat in vitro

Pharmacology ◽  
1996 ◽  
Vol 53 (5) ◽  
pp. 296-301 ◽  
Author(s):  
Manuel S&aacute;nchez ◽  
Luis Men&eacute;ndez. ◽  
Maria Jos&eacute; Garcia de Boto ◽  
Agust&iacute;n Hidalgo
Keyword(s):  
Cyclic Nucleotides ◽  
Testicular Capsule

The Role of Prostaglandins and Cyclic Nucleotides in Inflammation

1977 ◽  
pp. 323-344 ◽  
Author(s):  
J. P. Giroud ◽  
G. P. Velo ◽  
D. A. Willoughby
Keyword(s):  
Cyclic Nucleotides

Role of Cyclic Nucleotides in Excitable Cells

1980 ◽  
Vol 42 (1) ◽  
pp. 629-641 ◽  
Author(s):  
I Kupfermann
Keyword(s):  
Cyclic Nucleotides ◽  
Excitable Cells

scholarly journals Cytochemical methods for the localization of adenylate cyclase. A review and evaluation of the efficacy of the procedures.

1983 ◽  
Vol 31 (1) ◽  
pp. 85-93 ◽  
Author(s):  
L S Cutler
Keyword(s):  
Adenylate Cyclase ◽  
Cyclic Nucleotides ◽  
Cell Biology ◽  
Enzyme System ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Cellular Functions ◽  
Cytochemical Localization ◽  
Biochemical Evaluation

The cytochemical procedures for localizing adenylate cyclase have been a source of controversy since their introduction. The importance of cyclic adenosine monophosphate (AMP), the product of adenylate cyclase's action on adenosine triphosphate (ATP), in cell biology is clear. Thus, the ability to localize this enzyme system reliably is an important tool in the study of various cellular functions. This report reviews the literature and presents a biochemical evaluation of the methods for localizing adenylate cyclase. The review and data presented serve to clarify many of the controversies surrounding this important cytochemical procedure. It is evident that although there are problems associated with localizing the enzyme, several valid procedures are currently available for the cytochemical localization of adenylate cyclase. In using these procedures, the effects of fixation and the capture agent on adenylate cyclase activity in the particular tissue being studied should be considered. Only repurified adenylyl imidodiphosphate [App(NH)p] should be used in the incubation medium. If care is taken, the use of these techniques can be of great value in the continued study of the role of cyclic nucleotides in cell biology.

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