Rapid dephosphorylation of microtubule‐associated protein 2 in the rat brain hippocampus after pentylenetetrazole‐induced seizures

Abstract

We have studied the effect of Pentylenetetrazole (PTZ)‐induced seizures on the state of phosphorylation of microtubule‐associated protein 2 (MAP‐2) from rat hippocampus. A method for the in vivo32P‐labeling of hippocampal proteins has been established, consisting of intracerebro‐ventricular injection of 32PO4 of high specific activity. The results obtained indicate that PTZ induces a rapid and transient dephosphorylation of high‐molecular‐mass MAP‐2, which is prevented when the N‐methyl‐d‐asparatate receptor antagonist MK‐801 is previously administered. Phosphopeptide mapping of 32P‐labeled MAP‐2 obtained from hippocampi of PTZ‐treated rats reveals a pattern of phosphorylation distinct from that obtained from control saline‐treated rats or MK‐801 plus PTZ treated rats. We discuss the possible implications of N‐methyl‐d‐aspartate‐receptor activation and MAP‐2 dephosphorylation on the plastic changes induced in rat brain hippocampus after induced epileptiform activity. Copyright © 1993, Wiley Blackwell. All rights reserved