Selective PDE inhibitors rolipram and sildenafil improve object retrieval performance in adult cynomolgus macaques.
BACKGROUND
Selective phosphodiesterase (PDE) inhibitors improve the formation of hippocampus-dependent memories in several rodent models of cognition. However, studies evaluating the effects of PDE inhibition on prefrontal cortex-dependent cognition and in monkeys are rare.


OBJECTIVE
The present study investigates the effect of the PDE4 inhibitor rolipram and the PDE5 inhibitor sildenafil on object retrieval performance. Object retrieval is a prefrontal cortical-mediated task, which is likely to capture attention and response inhibition.


METHODS
The ability to retrieve a food reward from a clear box with an open side positioned in various orientations was assessed in adult male cynomolgus monkeys (Macaca fascicularis).


RESULTS
Rolipram (0.003-0.03 mg/kg, intramuscular [i.m.]) and sildenafil (0.3-3 mg/kg, i.m.) dose-dependently increased correct first reaches during difficult trials, reaching significance at 0.01 and 1 mg/kg, respectively. For both drugs, correct reaches were increased approximately 20%; that is, performance was improved from approximately 50 to approximately 70% correct.


CONCLUSIONS
Both rolipram and sildenafil improved object retrieval performance, thus demonstrating the cognition-enhancing effects of PDE inhibition on a prefrontal task of executive function in monkeys.
Rutten
K
K
Department of Neuroscience, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, PO Box 616, 6200 MD Maastricht, The Netherlands. k.rutten@np.unimaas.nl
Basile
J L
JL
Prickaerts
J
J
Blokland
A
A
Vivian
J A
JA
D000818:Animals; D001288:Attention / Q000187:drug effects / Q000502:physiology; D003071:Cognition / Q000187:drug effects / Q000502:physiology; D007273:Injections, Intramuscular; D008252:Macaca fascicularis; D008297:Male; D011939:Mental Recall / Q000187:drug effects* / Q000502:physiology; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D010879:Piperazines / Q000494:pharmacology*; D017397:Prefrontal Cortex / Q000187:drug effects / Q000502:physiology; D011340:Problem Solving / Q000187:drug effects / Q000502:physiology; D011597:Psychomotor Performance / Q000187:drug effects* / Q000502:physiology; D011687:Purines / Q000494:pharmacology; D020889:Rolipram / Q000494:pharmacology*; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000494:pharmacology*
D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D000068677:Sildenafil Citrate; D020889:Rolipram