PKMζ inactivation induces spatial familiarity

Diego Moncada,Haydée Viola

doi:10.1101/lm.1139508

Abstract

Spatial familiarization consists of a decrease in the exploratory activity over time after exposure to a place. Here, we show that a 30-min exposure to an open field led to a pronounced decrease in the exploratory behavior of rats, generating context familiarity. This behavioral output is associated with a selective decrease in hippocampal PKMzeta levels. A short 5-min exposure did not induce spatial familiarity or a decrease in PKMzeta, while inactivation of hippocampal PKMzeta by the specific inhibitor ZIP was sufficient to induce spatial familiarity, suggesting that the decrease in PKMzeta is involved in setting a given context as a familiar place.

Highlights

Rodents have an innate and spontaneous exploratory behavior
We found that a short exposure to a novel arena, in this case a 5-min open field (OF) session, led to an active exploration associated with a sequential rise in protein kinase A (PKA) activity and activation of the extracellular regulated kinases (ERKs) 1/2 and the ␣-subunit of calcium calmodulin-dependent protein kinase (CAMKII␣) in the hippocampus of rats (Vianna et al 2000)
We reported an increment in phosphorylated cAMP response element-binding protein levels, associated with the detection of a novel environment (Winograd and Viola 2004)

Summary

Introduction

Rodents have an innate and spontaneous exploratory behavior. When rats face a novel environment, they actively explore it in order to gather information about the place, and in subsequent exposures, their exploratory behavior begins to decrease. In both the SSF and MSF protocols, rats explored the arena for 30 min, which was the period of time previously found to be needed to induce spatial familiarity (Moncada and Viola 2006).

Results

Conclusion