Cyclic AMP-evoked oscillations of intracellular [Ca2+] in guinea-pig hepatocytes.
The effects of the beta-adrenoceptor agonist isoprenaline and cyclic AMP (cAMP) on cytosolic free Ca2+ ([Ca2+]i) were studied in the single guinea-pig hepatocyte. In common with InsP3-dependent agonists such as noradrenaline or angiotensin II, isoprenaline (0.5-10 microM) and cAMP (50-100 mM, perfused into the cell via the patch-pipette), were able to generate fast and slow fluctuations of [Ca2+]i. Responses to isoprenaline and cAMP also were observed in the absence of external Ca2+. Isoprenaline-evoked [Ca2+]i rises were not blocked by the intracellular perfusion of heparin, suggesting that these fluctuations are independent of the binding of InsP3 to its receptor.
Capiod
T
T
INSERM U274, Université Paris-Sud, Orsay, France.
Noel
J
J
Combettes
L
L
Claret
M
M
D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D000242:Cyclic AMP / Q000494:pharmacology*; D003600:Cytosol / Q000378:metabolism; D006168:Guinea Pigs; D006493:Heparin / Q000494:pharmacology; D007295:Inositol Phosphates / Q000378:metabolism; D007545:Isoproterenol / Q000494:pharmacology; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D009638:Norepinephrine / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000502:physiology; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000502:physiology
D007295:Inositol Phosphates; D015221:Potassium Channels; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D000804:Angiotensin II; D006493:Heparin; D000242:Cyclic AMP; D007545:Isoproterenol; D002118:Calcium; D009638:Norepinephrine