Verapamil and diltiazem inhibit receptor-operated calcium channels and intracellular calcium oscillations in rat hepatocytes

• Published in: FEBS letters Vol. 318; no. 3; pp. 341 - 344
• Main Authors: Striggow, Frank, Bohnensack, Ralf
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 08.03.1993; Elsevier
• Subjects: [Ca2+]i, intracellular free calcium concentration; Animals; Biological and medical sciences; Calcium - metabolism; Calcium Channels - drug effects; Calcium oscillation; Cell receptors; Cell structures and functions; Diltiazem; Diltiazem - pharmacology; Fluorescent Dyes; Fundamental and applied biological sciences. Psychology; Fura-2; Hormone receptors. Growth factor receptors. Cytokine receptors. Prostaglandin receptors; Liver - drug effects; Liver - metabolism; Male; Manganese - metabolism; Molecular and cellular biology; Phenylephrine - pharmacology; Rat hepatocyte; Rats; Rats, Wistar; Receptor-operated Ca 2+ channel; Receptor-operated Ca2+ channel; Receptors, Cell Surface - physiology; ROCCs, receptor-operated Ca2+ channels; Vasopressins - pharmacology; VDCCs, voltage-dependent Ca2+ channels; Verapamil; Verapamil - pharmacology; ROCCs, receptor-operated Ca 2+ channels; Receptor-operated Ca 2+ channel; Rat hepatocyte; [Ca 2+] i, intracellular free calcium concentration; Verapamil; Calcium oscillation; VDCCs, voltage-dependent Ca 2+ channels; Fura-2; Diltiazem; Vertebrata; Mammalia; Calcium; Hepatocyte; Rat; Membrane transport; Peptide hormone; Rodentia; Ionic channel; Neuropeptide; Vasopressin; Hormonal receptor
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(93)80542-3

Fura-2 loaded rat hepatocytes were used to determine whether the L-type channel blockers, verapamil and diltiazem, affect receptor-operated calcium channels (ROCCs). The flux through ROCCs was followed by quenching of fura-2 fluorescence due to the influx of extracellular Mn 2+ induced by vasopressin. Verapamil as well as diltiazem inhibited vasopressin-stimulated Mn 2+ influx in a dose-dependent manner up to 60% at concentrations of 200–400 μM. Furthermore, both inhibitors decreased significantly the frequency of phenylephrine-induced oscillation of [Ca 2+] i. The experimental findings indicate that L-type channel blockers inhibit ROCCs in rat hepatocytes.