The nitric oxide synthesis inhibitor L-NAME facilitates associative learning.
1. Nitric oxide has been suggested to play an important role in synaptic plasticity and in learning. 2. The authors examined the effects of NW-nitro-L-arginine methyl ester, a competitive and enantiomeric specific inhibitor of nitric oxide synthase, on classical conditioning of the rabbit's nictitating membrane response. 3. It was found that L-NAME significantly enhanced the acquisition of conditioned responses. 4. The enhanced conditioned responses were not due to a sensitization of the conditioned and unconditioned reflexes or to changes in baseline levels of responding. 5. The dose and route of administration of L-NAME employed in this study had no effect on blood pressure. 6. These results suggest that nitric oxide normally functions as a tonic inhibitory modulator of associative learning and that procedures aimed at decreasing its production may provide a novel approach for improving learning.
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Department of Pharmacology, Medical College of Pennsylvania, Philadelphia, USA.
Harvey
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JA
D000818:Animals; D001245:Association Learning / Q000187:drug effects*; D001767:Blinking / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D003214:Conditioning, Classical / Q000187:drug effects; D003216:Conditioning, Operant / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D011817:Rabbits
D004791:Enzyme Inhibitors; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester