Learning-specific, time-dependent increase in [3H]phorbol dibutyrate binding to protein kinase C in selected regions of the rat brain.
Several lines of evidence indicate that protein kinase C (PKC) participates in long-term potentiation (LTP) and in certain forms of learning. Here we describe a rapid, specific and time-dependent increase in [3H]phorbol-12,13-dibutyrate ([3H]PDBu) binding to membrane-associated PKC in selected brain regions of rats submitted to an inhibitory avoidance task. A quantitative film autoradiographic method was used to determine the amount and distribution of membrane-bound PKC in rats sacrificed at various time intervals after training. At 0, 30 and 120 min following training there was a prominent increase (up to 200%) in the binding of [3H]PDBu throughout the hippocampus relative to naive, shocked or habituated control groups. No significant changes in [3H]PDBu binding in any brain region were found at 180 min after training. Similar training-specific increments in the binding of [3H]PDBu were observed in the frontal, parietal and entorhinal cerebral cortices, amygdala and cerebellum. The maximal effect was seen at 30 min in the CA2 region of the hippocampus (+200%) and at 30 and 120 min after training in the amygdala (+170%) in comparison to naive control values. No alterations in [3H]PDBu binding were found in the other brain regions studied. The present findings, together with previous data reporting a similar temporal course in the effects of intrahippocampal or intraamygdala infusion of specific PKC inhibitors on memory, suggest that PKC activation plays a role in the acquisition and consolidation of an inhibitory avoidance learning.
Bernabeu
R
R
Instituto de Biología Celular, Facultad de Medicina, UBA, Paraguay, Argentina.
Izquierdo
I
I
Cammarota
M
M
Jerusalinsky
D
D
Medina
J H
JH
D000704:Analysis of Variance; D000818:Animals; D001345:Autoradiography; D001362:Avoidance Learning / Q000502:physiology*; D001921:Brain / Q000201:enzymology*; D005069:Evaluation Studies as Topic; D006624:Hippocampus / Q000378:metabolism; D017774:Long-Term Potentiation; D008297:Male; D015240:Phorbol 12,13-Dibutyrate / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism*; D011869:Radioligand Assay; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D014316:Tritium
D014316:Tritium; D015240:Phorbol 12,13-Dibutyrate; D011493:Protein Kinase C