Lysophosphatidic acid-induced Ca2+ mobilization in the neural retina of chick embryo

✍ Scribed by Zhou, Wen-Liang ;Sugioka, Miho ;Yamashita, Masayuki

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 186 KB
• Volume: 41
• Category: Article
• ISSN: 0022-3034
• DOI: 10.1002/(sici)1097-4695(199912)41:4<495::aid-neu5>3.0.co;2-k

✦ Synopsis

Lysophosphatidic acid (LPA) plays various roles in the regulation of cell growth as a lipid mediator. We studied the effect of LPA on intracellular Ca 2؉ concentration ([Ca 2؉ ] i ) with Fura-2 in the neural retina of chick embryo during neurogenesis. Bath application of LPA (1-100 M) to the embryonic day 3 (E3) chick retina caused an increase in [Ca 2؉ ] i in a dosedependent manner, with an EC 50 value of 9.2 M. The Ca 2؉ rise was also evoked in a Ca 2؉ -free medium, suggesting that release of Ca 2؉ from intracellular Ca 2؉ stores (Ca 2؉ mobilization) was induced by LPA. U-73122, a blocker of phospholipase C (PLC), inhibited the Ca 2؉ rise to LPA. Pertussis toxin partially inhibited the Ca 2؉ rise to LPA, indicating that G i /G o protein was at least partially involved in the LPA response. The developmental profile of the LPA response was studied from E3 to E13. The Ca 2؉ rise to LPA declined drastically from E3 to E7, in parallel with decrease in mitotic activity of retinal progenitor cells. The signal transduction pathway and developmental profile of the Ca 2؉ response to LPA were the same as those of the Ca 2؉ response to adenosine triphosphate (ATP), which enhances the proliferation of retinal progenitor cells. The coapplication of LPA with ATP resulted in enhancement of Ca 2؉ rise in the E3 chick retina. Our results show that LPA induces Ca 2؉ mobilization in the embryonic chick retina during neurogenesis.