Xenbase Image ID: 152485

Figure 1. Pharmacological Screen Implicates K+ and H+ Ion Flux in LR Patterning (A) K+ channel (BaCl2 and Chromanol 293B) and H+ pump (lansoprazole) inhibitors induced high incidences of heterotaxia. Batches of Xenopus embryos were exposed to ion channel and pump inhibitors between fertilization and stage 16 and scored for the laterality of the heart, stomach coiling, and gallbladder at stage 45. The incidence of heterotaxia in control embryos was about 1%. (B) H+/K+-ATPase blockers (omeprazole and SCH28080) induced heterotaxia whereas amiloride, EIPA, and cariporide (which inhibit Na+/H+ exchangers), ouabain (which inhibits Na+/K+-ATPase), and aurovertin (which inhibits the mitochondrial H+-ATPase) did not cause significant incidences of heterotaxia at doses that do not elicit anterioposterior defects. (C–G) Analysis of the situs of the heart, gut coiling, and gallbladder position of Xenopus embryos exposed H+/K+-ATPase inhibitors. Ventral views of stage 45 embryos are shown. Red arrowheads indicate the apex of the heart, yellow arrowheads indicate the direction of gut coiling, and green arrowheads indicate the gallbladder. (H and I) Example of normal heart in untreated and reversed heart in chick embryos injected in the albumin with lansoprazole and cultured in ovo to stage 15. Identical results were obtained with omeprazole and SCH28080. Image published in: Levin M et al. (2002) Copyright © 2002. Image reproduced with permission of the Publisher, Elsevier B. V. Larger Image Printer Friendly View

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