Effects of the neuroprotectant lubeluzole on the cytotoxic actions of veratridine, barium, ouabain and 6‐hydroxydopamine in chromaffin cells

• Published in: British journal of pharmacology 1998-07, Vol.124 (6), p.1187-1196
• Main Authors: Cano‐Abad, María F., López, Manuela G., Hernández‐Guijo, Jesús M., Zapater, Pedro, Gandía, Luis, Sánchez‐García, Pedro, García, Antonio G.
• Format: Article
• Language: English
• Subjects: 6‐hydroxydopamine; Adrenal Glands - cytology; Adrenal Glands - drug effects; Adrenal Glands - metabolism; Animals; Barium - pharmacology; Biological and medical sciences; Calcium - metabolism; Cattle; chromaffin cell; Chromaffin Cells - drug effects; Chromaffin Cells - metabolism; cytoprotection; Cytosol - metabolism; Cytotoxicity; lubeluzole; Medical sciences; Neuropharmacology; Neuroprotective agent; Neuroprotective Agents - pharmacology; ouabain; Ouabain - pharmacology; Oxidopamine - pharmacology; penfluridol; Penfluridol - pharmacology; Pharmacology. Drug treatments; Piperidines - pharmacology; R91154; Sodium - metabolism; Thiazoles - pharmacology; veratridine; Veratridine - pharmacology
• ISSN: 0007-1188; 1476-5381
• DOI: 10.1038/sj.bjp.0701955

1 Incubation of bovine adrenal chromaffin cells with veratridine (10–100 μm) during 24 h, caused a concentration‐dependent release of the cytosolic lactate dehydrogenase (LDH) into the bathing medium, an indicator of cell death. Lubeluzole or its R(−) enantiomer, R91154, did not enhance LDH release. Both lubeluzole and R91154 (0.3–10 μm) decreased the veratridine‐induced LDH release. 2 Penfluridol did not increase LDH release at concentrations 0.003–1 μm; 3–10 μm increased LDH release to 50–60%, after 24 h exposure. Penfluridol (0.03–0.3 μm) did not protect against the cytotoxic effects of veratridine; at 1 μm, 15% protection was produced. Higher concentrations (3–10 μm) enhanced the cytotoxic effects of veratridine. 3 Ba2+ ions caused a concentration‐dependent increase of LDH release. This cytotoxic effect was partially prevented by 3 μm lubeluzole and fully counteracted by 1 μm penfluridol. R91154 was less potent than lubeluzole and only protected against the lesion induced by 0.5 mm Ba2+. 4 Ouabain (10 μm during 24 h) increased LDH release to about 30%. Both lubeluzole (0.3–10 μm) and the lower concentrations of penfluridol (0.003–0.3 μm) prevented the ouabain cytotoxic effects. At higher concentrations (3 μm), penfluridol increased drastically the ouabain cytotoxic effects. 5 6‐Hydroxydopamine (6‐OHDA) caused significant cytotoxic effects at 30 and 100 μm. Lubeluzole (3–10 μm) or penfluridol (0.03–0.3 μm) had no cytoprotective effects against 6‐OHDA. 6 Lubeluzole (3 μm), R91154 (3 μm) and penfluridol (1 μm) blocked the current through Na+ channels in voltage‐clamped chromaffin cells (INa) by around 20–30%. Ca2+ current through Ca2+ channels (ICa) was inhibited 57% by lubeluzole and R91154 and 50% by penfluridol. The effects of penfluridol were not washed out, but those of lubeluzole and R91154 were readily reversible. 7 Lubeluzole (3 μm) induced reversible blockade of the oscillations of the cytosolic Ca2+, [Ca2+]i, in fura‐2‐loaded cells exposed to 30 or 100 μm veratridine. Penfluridol (1 μm) inhibited those oscillations in an irreversible manner. 8 The results suggest that lubeluzole and its R‐isomer caused cytoprotection against veratridine cell damage, by blocking the veratridine stimulated Na+ and Ca2+ entry, as well as the [Ca2+]i oscillations. The Ba2+ and ouabain cytotoxic effects were prevented more efficiently by penfluridol, likely by blocking the plasmalemmal Na+/Ca2+ exchanger. It remains dubious whether these findings are relevant to the