Inhibition of mGluR1 and IP3Rs impairs long-term memory formation in young chicks

Calcium (Ca2+) is involved in a myriad of cellular functions in the brain including synaptic plasticity. However, the role of intracellular Ca2+ stores in memory processing remains poorly defined. The current study explored a role for glutamate-dependent intracellular Ca2+ release in memory processing via blockade of metabotropic glutamate receptor subtype 1 (mGluR1) and inositol (1,4,5)-trisphosphate receptors (IP(3)Rs). Using a single-trial discrimination avoidance task developed for the young chick, administration of the specific and potent mGluR1 antagonist JNJ16259685 (500 nM, immediately post-training, ic), or the IP3R antagonist Xestospongin C (5 mu M, immediately post-training, ic), impaired retention from 90 min post-training. These findings are consistent with mGluR1 activating IP(3)Rs to release intracellular Ca2+ required for long-term memory formation and have been interpreted within an LTP2 model. The consequences of different patterns of retention loss following ryanodine receptor (RyR) and IP3R inhibition are discussed. (C) 2008 Elsevier Inc. All rights reserved.