Nitric oxide synthase inhibition does not impair visual or spatial discrimination learning

• Published in: Brain research Vol. 694; no. 1; pp. 177 - 182
• Main Authors: Tobin, Joseph R., Gorman, Linda K., Baxter, Mark G., Traystman, Richard J.
• Format: Journal Article
• Language: English
• Published: London Elsevier B.V 02-10-1995; Amsterdam Elsevier; New York, NY
• Subjects: Animals; Behavioral psychophysiology; Biological and medical sciences; Brain - metabolism; Choline acetyltransferase; Discrimination Learning - physiology; Fundamental and applied biological sciences. Psychology; Hemicholinium 3 - metabolism; Hemicholinium-3; Learning; Male; Memory; Miscellaneous; Neurotransmitter Uptake Inhibitors - metabolism; NG-Nitroarginine Methyl Ester - pharmacology; Nitric oxide; Nitric Oxide Synthase - antagonists & inhibitors; Nitric Oxide Synthase - metabolism; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Rats; Rats, Inbred F344; Space life sciences; Space Perception - physiology; Tissue Distribution; Visual Perception - physiology; Learning; Choline acetyltransferase; Nitric oxide; Memory; Hemicholinium-3; Rat; Enzyme; Rodentia; Enzyme inhibitor; Space perception; Nitric-oxide synthase; Vertebrata; Mammalia; Animal; Vision; Nitrogen monoxide; Oxidoreductases; Perceptive learning
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/0006-8993(95)00693-K

Nitric oxide (NO) is a candidate retrograde messenger involved in synaptic plasticity, and is linked to the cholinergic system in the brain. We examined the role of NO in the acquisition of visual and spatial discriminations by daily administration of either saline or 1-nitroarginine methyl ester (
l-NAME), an NO synthase inhibitor. Brains were assayed for NO synthase activity and two presynaptic cholinergic markers: hemicholinium-3 (HC-3) binding, which determines the number of sodium-dependent high-affinity choline uptake sites, and activity of choline acetyltransferase (ChAT), which is the synthetic enzyme for acetylcholine. In both behavioral tasks, the acquisition rate was not different between groups.
l-NAME reduced NO synthase activity by 85% in all brain areas assayed and HC-3 binding by 38% in hippocampus and 48% in posterior cortex. ChAT activity was not different between groups in any region assayed. These data suggest that NO does not play a role in visual or spatial discrimination learning. However, NO synthase inhibition may play a role in the regulation of cholinergic activity.