Postnatal development of inositol 1,4,5-trisphosphate receptors: a disparity with protein kinase C.
Ligand-stimulated phosphoinositide hydrolysis activates a bifurcating second messenger system, releasing inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DG), which activates protein kinase C (PKC). Yet, in developing cat visual cortex and hippocampus, high levels of [3H]PDBu binding (labelling PKC) appear much earlier than do [3H]IP3 labelled sites. Binding distributions for the two ligands also appear to be complimentary in both brain regions. Moreover, early surgical removal of input to the visual cortex increases [3H]PDBu binding without affecting that of [3H]IP3. Our results suggest that, (1) at certain developmental stages, IP3 and PKC may act individually or complimentarily rather than synergistically in the visual cortex and hippocampus; (2) in neonatal cortex, IP3 metabolites rather than IP3 itself may act as second messengers; (3) although both IP3 receptors and PKC are localized in intracortical cells, their expression is regulated by different mechanisms during development.
Jia
W W
WW
Department of Ophthalmology, University of British Columbia, Vancouver, Canada.
Liu
Y
Y
Cynader
M
M
D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development*; D001665:Binding Sites / Q000502:physiology; D015220:Calcium Channels; D002415:Cats; D006624:Hippocampus / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D053496:Inositol 1,4,5-Trisphosphate Receptors; D015240:Phorbol 12,13-Dibutyrate; D011493:Protein Kinase C / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear; D015290:Second Messenger Systems / Q000502:physiology; D014793:Visual Cortex / Q000737:chemistry / Q000378:metabolism
D015220:Calcium Channels; C506926:ITPR1 protein, human; D053496:Inositol 1,4,5-Trisphosphate Receptors; D018160:Receptors, Cytoplasmic and Nuclear; D015240:Phorbol 12,13-Dibutyrate; D011493:Protein Kinase C