Zaprinast consolidates long-term memory when administered to neonate chicks trained using a weakly reinforced single trial passive avoidance task.
A weakly reinforced variant of the single trial passive avoidance task developed for the day-old chick typically fails to consolidate long-term memory. However, administration of zaprinast, a phosphodiesterase (PDE) type 5 inhibitor, (ic; 10 microl/side) immediately post-training resulted in a dose-dependent increase in retention at test 180 min post-training. Further, 100 microM zaprinast resulted in high levels of retention at test 180 min post-training when administered from 10 min before training to 10 min after training. Finally, 100 microM zaprinast, when administered immediately post-training, resulted in the consolidation of long-term memory at a number of times of test extending as late as 24 h post-training. Inhibition of PDE type 5 is known to increase cellular cGMP levels. Previous investigations using a strongly reinforced variant of this task have suggested a role for cGMP in memory retrieval, we now postulate that cGMP is also necessary for memory formation in chicks trained using passive avoidance.
School of Psychology, Psychiatry and Psychological Medicine, Faculty of Medicine, Nursing and Health Sciences, Monash University, Wellington Rd., Clayton, Vic. 3800, Australia.
Emma
E
Campbell
Thomas
T
Edwards
D015106:3',5'-Cyclic-GMP Phosphodiesterases / Q000037:antagonists & inhibitors*; D000704:Analysis of Variance; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D002645:Chickens; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D018697:Nootropic Agents / Q000008:administration & dosage*; D011688:Purinones / Q000008:administration & dosage*; D012054:Reinforcement, Psychology; D012153:Retention, Psychology / Q000187:drug effects*
D018697:Nootropic Agents; D011688:Purinones; D015106:3',5'-Cyclic-GMP Phosphodiesterases; C011145:zaprinast