A mutation in the AMPA-type glutamate receptor, glr-1, blocks olfactory associative and nonassociative learning in Caenorhabditis elegans

The alpha -amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA)-type iono tropic glutamate receptor mediates fast excitatory neurotransmission in the vertebrate brain and is important for synaptic plasticity and the initial induction of long-term potentiation (LTP). This study found that the putati ve Caenorhabditis elegans AMPA receptor gene. glr-1. plays a significant ro le in experience-dependent behavior in C. elegans. glr-1 mutants are defici ent in an olfactory associative learning task, in which diacetyl (DA) is pa ired with acetic acid solution. glr-1 mutant nematodes are also impaired in nonassociative learning (habituation) with the same DA stimulus. The C ele gans learning mutants, lrn-1 and lrn-2. are impaired in chemosensory associ ative learning yet have no deficits in habituation. The results suggest tha t although associative and nonassociative learning can be genetically disso ciated (lrn-1 and lrn-2), they also share some common molecular processes, including glr-1-mediated neurotransmission.