Inositol 1,4,5-trisphosphate signals the motile response of fish chromatophores—I. Aggregation of pigment in the tilapia melanophore
✍ Scribed by Fujii, Ryozo ;Wakatabi, Hoshitsugu ;Oshima, Noriko
- Publisher
- John Wiley and Sons
- Year
- 1991
- Tongue
- English
- Weight
- 878 KB
- Volume
- 259
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
Abstract
After permeabilization of the cell membrance by the treatment with a surfactant, Brij 58, inositol 1,4,5‐trisphosphate (IP~3~) was found to be effective in causing aggregation of melanosomes within melanophores in primary cultures of the tilapia, Oreochromis niloticus. Inositol 1‐monophosphate (IP) and 1,4‐bisphosphate (IP~2~) did not have such an effect. Phentolamine, an alpha‐adrenolytic agent, and prazosin, a more specific alpha~1~‐blocker, did not interfere with the action of IP~3~, even though they were effective in antagonizing the aggregation of pigment in response to norepinephrine. It appears, therefore, that IP~3~ may function as an intracellular physiological mediator in the signal transduction of pigment‐aggregating stimuli, including at least alpha~1~‐adrenergic stimuli, possibly via the release of Ca^2+^ from the intracellular compartments in which they are stored.