Environmental stimulation promotes changes in the distribution of phorbol ester receptors.
The translocation of protein kinase C (PKC) from the cytosol to the membrane might be functionally involved in learning and memory. Using [3H]-phorbol 12,13-dibutyrate (3H-PDBu) binding three pools of binding sites could be distinguished in tissue preparations: Pool a comprised the soluble receptors which bound phorbol ester with low affinity in the absence of calcium. Pool b was composed of high-affinity phorbol ester binding sites identified in the soluble fraction upon addition of calcium. Pool c represented stably membrane-bound receptors binding phorbol ester independently of calcium. 3H-PDBu binding was then measured in the cortices and hippocampi of rats trained in an eight-arm radial maze. A progressive training-dependent increase of membrane-bound binding activity with a concomitant decrease in the soluble fraction was detected independent of learning the maze task. These results suggest that it is the experience of an enriched environment by the repeated behavioral stimulation in a maze rather than the acquisition of a memory task that leads to enhanced incorporation of phorbol ester receptors (PKC) into the cell membrane.
Spieler
K
K
Pharma Division, Preclinical Research, F. Hoffmann-La Roche Ltd, Basel, Switzerland.
Schoch
P
P
Martin
J R
JR
Haefely
W
W
D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects; D029742:Caenorhabditis elegans Proteins; D002118:Calcium / Q000378:metabolism; D002352:Carrier Proteins; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D003600:Cytosol / Q000201:enzymology / Q000378:metabolism; D004533:Egtazic Acid / Q000494:pharmacology; D004777:Environment; D005260:Female; D066298:In Vitro Techniques; D007858:Learning / Q000187:drug effects; D015240:Phorbol 12,13-Dibutyrate / Q000493:pharmacokinetics / Q000494:pharmacology*; D011493:Protein Kinase C / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011955:Receptors, Drug / Q000187:drug effects / Q000378:metabolism*; D013028:Space Perception / Q000187:drug effects
D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D011955:Receptors, Drug; C083141:phorbol ester binding protein; C027776:phorbol ester receptor; D015240:Phorbol 12,13-Dibutyrate; D004533:Egtazic Acid; D011493:Protein Kinase C; D002118:Calcium