Inositol uptake and metabolism in molluscan neuronal tissue.
The uptake of myo-[3H]inositol into neurones from Lymnaea stagnalis has been demonstrated to be a sodium-dependent process, saturable with a Km of approximately 50 microM and shown to be linear with time for at least 120 min. The rate of transport of myo-inositol into the cell appears to influence directly its incorporation into neuronal lipids. Using anion-exchange high-performance liquid chromatography, we have demonstrated a high rate of breakdown of phosphatidylinositol 4,5-bisphosphate in Lymnaea nerve under basal conditions. Stimulation with carbamylcholine enhanced production of inositol 1-phosphate, inositol bisphosphate, inositol 1,4,5-trisphosphate, and inositol 1,3,4-trisphosphate. Formation of inositol tetrakisphosphate was not detected. Electrical stimulation also caused an increased formation of inositol phosphates. These results provide evidence for an active myo-inositol transport system in molluscan neurones and suggest that the hydrolysis of inositol lipids may play a role as an intracellular signalling system in this tissue.
Tuersley
M D
MD
Department of Medicine, University of Manchester, England.
Best
L
L
Tomlinson
S
S
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002217:Carbachol / Q000494:pharmacology; D002462:Cell Membrane / Q000378:metabolism; D004558:Electric Stimulation; D006868:Hydrolysis; D007294:Inositol / Q000378:metabolism*; D015544:Inositol 1,4,5-Trisphosphate; D007295:Inositol Phosphates / Q000378:metabolism; D007700:Kinetics; D008195:Lymnaea / Q000378:metabolism*; D008563:Membrane Lipids / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D012964:Sodium / Q000494:pharmacology; D010738:Type C Phospholipases / Q000378:metabolism
D007295:Inositol Phosphates; D008563:Membrane Lipids; C002647:inositol 1-phosphate; C044259:inositol 1,4-bis(phosphate); D007294:Inositol; D015544:Inositol 1,4,5-Trisphosphate; D002217:Carbachol; D012964:Sodium; D010738:Type C Phospholipases