5-Hydroxytryptamine affects turnover of polyphosphoinositides in maize and stimulates nitrate reductase in the absence of light.
Incubation of etiolated maize leaves for 5 min in 5-hydroxytryptamine increased phosphatidylinositol-4,5-bisphosphate levels but on longer incubation its level decreased and a corresponding increase in inositol-trisphosphate was observed. The increase in phosphatidylinositol-4,5-bisphosphate by 5-hydroxytryptamine was similar to that obtained after short irradiation of leaves with red light. Nitrate-inducible and phytochrome-stimulated enzyme nitrate reductase could be stimulated in darkness if the leaves were incubated in the presence of nitrate and 5-hydroxytryptamine. These results indicate that one of the initial events in phytochrome-mediated enzyme stimulation could be through the generation of 'signals' from the turnover of the phosphoinositide cycle.
Chandok
M R
MR
Molecular Plant Physiology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India.
Sopory
S K
SK
D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D008027:Light; D050901:Nitrate Reductase; D009565:Nitrate Reductases / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism*; D010834:Phytochrome / Q000378:metabolism; D012701:Serotonin / Q000494:pharmacology*; D003313:Zea mays / Q000187:drug effects* / Q000378:metabolism
D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates; D010834:Phytochrome; D012701:Serotonin; D015544:Inositol 1,4,5-Trisphosphate; D009565:Nitrate Reductases; D050901:Nitrate Reductase