Incorporation of [32P]orthophosphate into brain-slice phospholipids and their precursors. Effects of electrical stimulation

Abstract

1. The incorporation of [(32)P]phosphate into phospholipids was measured in slices cut from the pial surface of guinea-pig cerebral cortex; incorporation into the phosphorus of some water-soluble precursors of phospholipid was measured under similar conditions. 2. Slices subjected to overall electrical stimulation at a frequency of 5pulses/sec. differed from control slices in their pattern of phospholipid labelling. After 1hr. of stimulation, incorporation of [(32)P]phosphate into phosphatidylcholine, ethanolamine phospholipid and cardiolipin was respectively 54, 55 and 58% of the control value, and that into phosphatidylinositol was 186% of control. Phosphatidic acid labelling tended to increase with electrical stimulation, but the statistical significance of this change was marginal. Labelling of phosphatidylglycerol and di- and tri-phosphoinositides was not affected significantly by electrical stimulation. 3. Electrical stimulation of the tissue altered the specific radioactivities of water-soluble precursors of phospholipid. 4. The turnover rates of the phosphate groups of phospholipids were estimated approximately from the specific radioactivities of phospholipids and their precursors. Phosphatidylinositol (and its lipid-soluble precursors) showed the largest change in turnover rate in response to electrical stimulation of the tissue; the turnover rates of other lipids were also affected. Changes in the specific radioactivity of phospholipids did not correspond to changes in turnover in these experiments.

The association between phosphatidylinositol phosphodiesterase activity and a specific subunit of microtubular protein in rat brain

“…Hormonal stimulation of phosphatidylinositol turnover has been demonstrated in thyroid gland treated with pituitary thyrotrophin (Scott et al, 1968), in rat heart after adrenaline administration (Gaut & Huggins, 1966), and in adipose tissue stimulated with insulin (De Torrentegui & Berthet, 1966). Similar effects have been observed in nervous tissue after electrical stimulation (Larrabee & Leicht, 1965;Pumphrey, 1969) or treatment with acetylcholine (Hokin, 1970). Double-labelling experiments in which radioisotope was incorporated into the glycerol or fatty acid moiety of the phospholipid indicated Vol.…”

Effect of ADP‐induced Shape Change on Incorporation of 32P into Platelet Phosphatidic Acid and Mono‐, Di‐ and Triphosphatidyl Inositol

“…Further experiments indicated that the increase in labelling of PA may represent synthesis, or an increase in the size, of a small pool of PA (Lloyd et al, 1973). Similar changes in labelling of PA and MPI with 32P from 3 2 P 0 4 have been observed in other tissucs such as exocrine pancreas during secretion (Hokin, 1969), nervous tissue during depolarization (Pumphrey, 1969) and white cells during phagocytosis (Sastry & Hokin, 1966).…”

Phospholipid profile of developing heart of rats exposed to low-protein diet in pregnancy

“…Myocardial tissue of rats at 1, 3, 5, 7, and 21 days of age was treated with a mixture of chloroform and methanol (2:1, vol/vol) to extract lipids (13). The total lipid extract (TLE), as well as a mixture of authentic phospholipid standards, was subjected to two-dimensional thin-layer chromatography (TLC) on silica gel 60-Å K6F TLC plates (Whatman International, Maidstone, UK) (39). The migration of these phospholipids was identified after a brief exposure of TLC plates to iodine.…”