Regulation of force and intracellular calcium transients by cyclic AMP generated by forskolin, MDL 17,043 and isoprenaline, and its modulation by muscarinic receptor agents: a novel mechanism for accentuated antagonism

1989 ◽  
pp. 69-83
Author(s):  
Masao Endoh
Keyword(s):  
Cyclic Amp ◽  
Intracellular Calcium ◽  
Muscarinic Receptor ◽  
Calcium Transients

scholarly journals Intracellular calcium and adenosine 3′,5′-cyclic monophosphate as mediators of potassium-induced aldosterone secretion

1985 ◽  
Vol 228 (1) ◽  
pp. 69-76 ◽  
Author(s):  
I Kojima ◽  
K Kojima ◽  
H Rasmussen
Keyword(s):  
Arachidonic Acid ◽  
Cyclic Amp ◽  
Intracellular Calcium ◽  
Secretory Response ◽  
Ionophore A23187 ◽  
Small Decrease ◽  
Aldosterone Secretion ◽  
Cyclic Monophosphate ◽  
A Value ◽  
Glomerulosa Cells

We compared the action of K+ on aldosterone secretion from isolated bovine adrenal glomerulosa cells with that of ionophore A23187. Addition of either 50 nM-A23187 or 8 mM-K+ to perifused cells induces a similar initial aldosterone-secretory responses, and a similar sustained increases in Ca2+ entry. However, K+-induced secretion is more sustained than is A23187-induced secretion, even though each agonist appears to act by increasing Ca2+ entry into the cells. When [3H]inositol-labelled cells are stimulated by 8 mM-K+, a small decrease in phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] is observed. This decrease is not accompanied by an increase in inositol trisphosphate (InsP3) concentration. Also, if [3H]arachidonic acid-labelled cells are exposed to 8 mM-K+, there is no increase in [3H]diacylglycerol production. When [3H]inositol-labelled cells are stimulated by 50 nM-A23187, a small decrease in PtdIns(4,5)P2 is observed. This decrease is not accompanied by an increase in InsP3. The cyclic AMP content of K+-treated cells was approximately twice that in A23187-treated cells. If cells are perifused simultaneously with 50 nM-forskolin and 50 nM-A23187, the initial aldosterone-secretory response is similar to that induced by A23187 alone, and the response is sustained rather than transient, and is similar to that seen during perifusion of cells with 8 mM-K+. This dose of forskolin (50 nM) causes an elevation of cyclic AMP concentration in A23187-treated cells, to a value similar to that in K+-treated cells. These results indicate that, in K+-treated cells, a rise in cyclic AMP content serves as a positive sensitivity modulator of the Ca2+ message, and plays a key role in mediating the sustained aldosterone-secretory response.

Caffeine attenuates contraction-induced diminutions of the intracellular calcium transient in mouse lumbrical muscle ex vivo

2019 ◽  
Vol 97 (5) ◽  
pp. 429-435 ◽  
Author(s):  
Ian C. Smith ◽  
Rene Vandenboom ◽  
A. Russell Tupling
Keyword(s):  
Skeletal Muscle ◽  
Intracellular Calcium ◽  
Calcium Release ◽  
Ex Vivo ◽  
Calcium Transient ◽  
Calcium Transients ◽  
Inotropic Effects ◽  
Intracellular Calcium Transient ◽  
Lumbrical Muscle ◽  
Lumbrical Muscles

The amount of calcium released from the sarcoplasmic reticulum in skeletal muscle rapidly declines during repeated twitch contractions. In this study, we test the hypothesis that caffeine can mitigate these contraction-induced declines in calcium release. Lumbrical muscles were isolated from male C57BL/6 mice and loaded with the calcium-sensitive indicator, AM-furaptra. Muscles were then stimulated at 8 Hz for 2.0 s in the presence or absence of 0.5 mM caffeine, at either 30 °C or 37 °C. The amplitude and area of the furaptra-based intracellular calcium transients and force produced during twitch contractions were calculated. For each of these measures, the values for twitch 16 relative to twitch 1 were higher in the presence of caffeine than in the absence of caffeine at both temperatures. We conclude that caffeine can attenuate contraction-induced diminutions of calcium release during repeated twitch contractions, thereby contributing to the inotropic effects of caffeine.

Morphine coupling to invertebrate immunocyte nitric oxide release is dependent on intracellular calcium transients

1999 ◽  
Vol 123 (3) ◽  
pp. 295-299 ◽  
Author(s):  
Fernando E Nieto-Fernandez ◽  
Dwight Mattocks ◽  
Francesco Cavani ◽  
Michel Salzet ◽  
George B Stefano
Keyword(s):  
Nitric Oxide ◽  
Intracellular Calcium ◽  
Calcium Transients ◽  
Nitric Oxide Release

Inverse correlation of intracellular calcium and cyclic AMP levels in renal cell carcinoma

2012 ◽  
Vol 30 (8) ◽  
pp. 619-622 ◽  
Author(s):  
Ujjawal Sharma ◽  
Shrawan Kumar Singh ◽  
Prasad Rajendra
Keyword(s):  
Renal Cell Carcinoma ◽  
Cyclic Amp ◽  
Intracellular Calcium ◽  
Cell Carcinoma ◽  
Renal Cell ◽  
Inverse Correlation
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