Otentiation and Prolongation of Long-term Odor Emory in Neonate Rats Using a Phosphodiesterase Nhibitor

bstract—Cyclic AMP has been shown to have a critical role n learning and memory in invertebrates. Here we use the rat up odor preference learning model in which odor acts as a onditioned stimulus and -adrenoceptor stimulation acts as n unconditioned stimulus to test the role of cyclic AMP in an ssociative mammalian paradigm. A phosphodiesterase inibitor that prevents cyclic AMP breakdown (cilomilast) akes a low, learning-ineffective dose of a -adrenoceptor gonist (isoproterenol, 1 mg/kg) an effective unconditioned timulus in pup odor preference learning. A dose of the hosphodiesterase inhibitor (cilomilast, 1 mg/kg) that inuces learning with a weak unconditioned stimulus interferes ith learning using a normally optimal unconditioned stimuus (isoproterenol, 2 mg/kg). Cilomilast (3 mg/kg) paired with eppermint odor during learning, prolonged memory at least our times longer than without the drug (24 h vs. 96 h). These ata demonstrate a causal role for cyclic AMP in the acquiition and duration of odor preference learning in the rat pup. 2005 Published by Elsevier Ltd on behalf of IBRO.