title: Difference between the effects of atrial natriuretic peptide and calcium antagonist on cytosolic free calcium in cultured vascular smooth muscle cells.
abstract: The effect of atrial natriuretic peptide (ANP) on cytosolic free calcium ([Ca2+]i) was studied in monolayers of cultured vascular smooth muscle (VSM) cells loaded with a fluorescent calcium indicator, fura-2. ANP (atriopeptin III, 10(-8) M) decreased the resting level of [Ca2+]i and sustained rises in [Ca2+]i following peak levels induced by vasoconstrictive hormones (angiotensin II or vasopressin). ANP also decreased a rise in [Ca2+]i induced by high potassium (high K+) depolarization. The initial rise in [Ca2+]i induced by vasopressin was not inhibited by ANP. On the other hand, calcium antagonists (nicardipine or nifedipine) inhibited the high K+-induced rise in [Ca2+]i, whereas there was no effect on rises in [Ca2+]i induced by vasopressin. These results suggest that calcium antagonists inhibit voltage-dependent calcium channels, while ANP can decrease [Ca2+]i presumably through a stimulation of calcium-extrusion active transports in vascular smooth muscle cells.
authors: Second Department of Internal Medicine, Tohoku University, School of Medicine, Sendai, Japan.
authors: K
authors: K
authors: Takeuchi
authors: K
authors: K
authors: Abe
authors: M
authors: M
authors: Yasujima
authors: M
authors: M
authors: Sato
authors: Y
authors: Y
authors: Kasai
authors: K
authors: K
authors: Tsunoda
authors: T
authors: T
authors: Hagino
authors: M
authors: M
authors: Kanazawa
authors: K
authors: K
authors: Yoshinaga
mesh_terms: D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism*; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D009529:Nicardipine / Q000494:pharmacology; D009543:Nifedipine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013050:Spectrometry, Fluorescence
chemical_list: D002121:Calcium Channel Blockers; D009320:Atrial Natriuretic Factor; D009529:Nicardipine; D009543:Nifedipine; D002118:Calcium