Lithium decreases turnover of arachidonate in several brain phospholipids.
In vivo rates of incorporation and turnover of palmitate and arachidonate in brain phospholipids were measured in awake rats treated chronically with lithium, following intravenous infusion of radiolabeled palmitate and arachidonate, respectively. Chronic lithium, at a brain level considered to be therapeutic in humans, decreased turnover of arachidonate within brain phosphatidylinositol, phosphatidylcholine and phosphatidylethanolamine by up to 80% (P < 0.001). In contrast, lithium had a minimal effect on turnover of palmitate, causing only a 26% reduction in turnover in phosphatidylcholine (P < 0.01). These results suggest that a major therapeutic effect of lithium is to reduce turnover specifically of arachidonate, possibly by inhibiting phospholipase A2 involved in signal transduction. The effect may be secondary to the known action of lithium on the phosphoinositide cycle, by inhibiting the activity of inositol monophosphatase.
Chang
M C
MC
Laboratory of Neurosciences, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892-1582, USA. mcjchang@box-m.nih.gov
Grange
E
E
Rabin
O
O
Bell
J M
JM
Allen
D D
DD
Rapoport
S I
SI
D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism*; D001923:Brain Chemistry / Q000187:drug effects*; D003864:Depression, Chemical; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D007700:Kinetics; D008094:Lithium / Q000494:pharmacology*; D008297:Male; D019308:Palmitic Acid / Q000378:metabolism; D010171:Palmitoyl Coenzyme A / Q000378:metabolism; D010713:Phosphatidylcholines / Q000378:metabolism; D010714:Phosphatidylethanolamines / Q000378:metabolism; D010716:Phosphatidylinositols / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism*; D051381:Rats; D011916:Rats, Inbred F344; D015398:Signal Transduction / Q000502:physiology
D005230:Fatty Acids, Nonesterified; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D010716:Phosphatidylinositols; D010743:Phospholipids; D010171:Palmitoyl Coenzyme A; D016718:Arachidonic Acid; D019308:Palmitic Acid; D008094:Lithium