The acute and long-term effects of ethanol on voltage-dependent Ca channel function were studied in PC12, a clonal cell line of neural crest origin. Acute exposure to ethanol produced a concentration-dependent decrease in depolarization-evoked 45Ca2 uptake, while prolonged (2-10 days) exposure led to a reciprocal increase in 45Ca2+ uptake and in the number of Ca-channel binding sites labeled by the dihydropyridine Ca-channel antagonist [3H]nitrendipine. Uptake was restored to control levels following withdrawal of ethanol from cultures. These findings indicate that cellular adaptation to ethanol may involve enhanced expression of dihydropyridine-sensitive, voltage-dependent Ca channels.The ability of ethanol to inhibit voltage-dependent Ca2+ influx (1-5) may contribute to alterations in neuronal function that underlie acute ethanol intoxication. The development of tolerance to the ethanol effect on Ca2+ influx (4, 6) further suggests a role for voltage-dependent Ca channels in cellular adaptation to prolonged ethanol exposure. However, the molecular basis for regulation of Ca-channel function by ethanol is unknown. It has recently become possible to explore this problem directly, using neural cell lines in which voltage-dependent Ca2+ flux can be measured by radioisotopic methods (7)(8)(9) and Ca-channel radioligands that label channel-associated drug receptor sites with high affinity and specificity (10).PC12, a clonal cell line of neural crest origin, expresses voltage-dependent Ca channels demonstrable by electrophysiologic (11) and radioisotopic (7,8) techniques. K+-stimulated 45Ca2+ uptake into PC12 cells exhibits classical properties of ion flux through voltage-dependent Ca channels, including inhibition by cationic Ca-channel blockers (7, 12) and insensitivity to the Na-channel blocker tetrodotoxin (7). 45Ca2+ uptake into PC12 cells is also sensitive to inhibition by organic Ca-channel antagonists (8,13), and enhancement by Ca-channel agonists (12), and is coupled to binding sites for 3H-labeled dihydropyridine Ca-channel antagonists (8).Thus, Ca channels in PC12 cells appear to resemble one subtype of (dihydropyridine-sensitive) voltage-dependent Ca channel present in mammalian neurons (14). We have used this cell line to evaluate the role of voltage-dependent Ca channels in the adaptation of neural cells to ethanol. 45Ca2+ Uptake. Cells were plated onto polylysine-coated Falcon six-well (9.6-cm2) plastic tissue culture dishes 2 days before assay (for studies of acute alcohol exposure) or 2-10 days before assay (for experiments involving long-term exposure). The initial plating density was varied between 0.8 and 1.6 x 106 cells per well to accommodate exposures of different duration, with ethanol-treated and parallel control cultures plated at the same density in each case. Cells were rinsed with 1 ml of 5 mM K+ buffer (85 mM NaCl, 45 mM choline chloride, 5 mM KCl, 2 mM CaCl2, 5 mM glucose, and 50 mM Hepes at pH 7.4), and preincubated for 25 min in 1 ml of fresh buffer with or without added alcoh...

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Sporadic platinum resistant high grade serous ovarian cancer* n=30 290 mg n=5 210 mg n=6 150 mg n=6 110 mg n=5 80 mg n=6 60 mg n=7 40 mg n=3 30 mg n=6 Key Inclusion and Exclusion Criteria Inclusion criteria • Parts A&B Age 18 or older Confirmed histological diagnosis Informed consent Adequate organ function ECOG PS of ≤ 2