scholarly journals Lithium inhibits muscarinic-receptor-stimulated inositol tetrakisphosphate accumulation in rat cerebral cortex

1987 ◽  
Vol 247 (3) ◽  
pp. 797-800 ◽  
Author(s):  
I Batty ◽  
S R Nahorski
Keyword(s):  
Cerebral Cortex ◽  
Steady State ◽  
Inhibitory Action ◽  
Rat Cerebral Cortex ◽  
Phosphoinositide Metabolism ◽  
Muscarinic Agonist ◽  
Complex Action ◽  
Inositol 1,4,5 Trisphosphate ◽  
Inositol Tetrakisphosphate ◽  
Cortex Slices

The effects of Li+ on carbachol-stimulated phosphoinositide metabolism were examined in rat cerebral-cortex slices labelled with myo-[2-3H]inositol. The muscarinic agonist carbachol evoked an enhanced steady-state accumulation of [3H]inositol monophosphate ([3H]InsP1), [3H]inositol bisphosphate ([3H]InsP2), [3H]inositol 1,3,4-trisphosphate ([3H]Ins(1,3,4)P3), [3H]inositol 1,4,5-trisphosphate ([3H]Ins(1,4,5)P3) and [3H]inositol tetrakisphosphate ([3H]InsP4). Li+ (5 mM), after a 10 min lag, severely attenuated carbachol-stimulated [3H]InsP4 accumulation while simultaneously potentiating accumulation of both [3H]InsP1 and [3H]InsP2 and, at least initially, of [3H]Ins(1,3,4)P3. These data are consistent with inhibition of inositol mono-, bis- and 1,3,4-tris-phosphate phosphatases to different degrees by Li+ in brain, but are not considered to be completely accounted for in this way. Potential direct and indirect mechanisms of the inhibitory action of Li+ on [3H]InsP4 accumulation are considered. The present results stress the complex action of Li+ on cerebral inositol metabolism and indicate that more complex mechanisms than are yet evident may regulate this process.

scholarly journals Stimulation by acetylcholine of phosphatidylinositol labelling. Subcellular distribution in rat cerebral-cortex slices

1972 ◽  
Vol 126 (5) ◽  
pp. 1141-1147 ◽  
Author(s):  
Eduardo G. Lapetina ◽  
Robert H. Michell
Keyword(s):  
Cerebral Cortex ◽  
Specific Radioactivity ◽  
Neuronal Cell ◽  
Subcellular Fractionation ◽  
Rat Cerebral Cortex ◽  
Marker Enzymes ◽  
Fresh Tissue ◽  
Cell Structures ◽  
Neuronal Cell Bodies ◽  
Cortex Slices

1. Rat cerebral-cortex slices were incubated with 32Pi, acetylcholine and eserine for periods of 10min and 2h. The specific radioactivity of phosphatidylinositol was elevated during these treatments by 36 and 106% respectively. 2. The specific radioactivities of the phosphatidylinositol in different cell structures were determined after subcellular fractionation. They were highest in the nuclear, microsomal and synaptic-vesicle fractions and lowest in myelin, both in the controls and in the acetylcholine-treated slices. 3. The stimulated labelling of phosphatidylinositol was relatively evenly distributed: no subcellular fraction showed a stimulation markedly higher than that in the homogenate. 4. Studies of the distributions and activities of marker enzymes indicated that the subcellular fractionation achieved was similar to that with fresh tissue. 5. The results are discussed in relation to the previous report that the stimulation is observed throughout the neuronal cell-bodies and in relation to the hypothesis that the labelled phosphatidylinositol produced by stimulation is a component of an acetylcholine-receptor proteolipid localized in the synaptic junction.

Phosphorylation of MARCKS by endothelin in rat cerebral cortex slices

1999 ◽  
Vol 24 (3) ◽  
pp. 155-162 ◽  
Author(s):  
Mar�a J. P�rez-Alvarez ◽  
M. Carmen Calcerrada ◽  
R. Edgardo Catal�n ◽  
Ana M. Mart�nez
Keyword(s):  
Cerebral Cortex ◽  
Rat Cerebral Cortex ◽  
Cortex Slices
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