Nitric oxide may underlie learned fear in the elevated T-maze
| Autor: | Moacir Serralvo Faria, Nadine Vandresen, A.V. Calixto, H. Moreno, Gilberto De Nucci |
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| Rok vydání: | 2001 |
| Předmět: |
Male
medicine.medical_specialty Midazolam Blood Pressure Escape response Nitric Oxide Inhibitory postsynaptic potential Nitric oxide chemistry.chemical_compound Internal medicine Avoidance Learning medicine Animals Enzyme Inhibitors Rats Wistar Maze Learning Increased mean arterial pressure Baseline values Behavior Animal Dose-Response Relationship Drug biology Chemistry General Neuroscience Brain Fear T-maze Rats Nitric oxide synthase NG-Nitroarginine Methyl Ester Endocrinology Anti-Anxiety Agents Enzyme inhibitor biology.protein Nitric Oxide Synthase |
| Zdroj: | Brain Research Bulletin. 55:37-42 |
| ISSN: | 0361-9230 |
| DOI: | 10.1016/s0361-9230(01)00480-4 |
| Popis: | The present study evaluated the role of nitric oxide (NO) in learned and innate fear in rats submitted to the elevated T-maze (ETM). Learned and innate fear were evaluated through the inhibitory avoidance and escape behaviour from the open arms, respectively. Rats treated with the inhibitor of NO synthesis N ω -nitro-L-Arginine methyl ester (L-NAME; 5, 10, and 50 mg · kg −1 ) were able to learn the inhibitory avoidance. However, L-NAME (50 mg · kg −1 ), but not its inert isomer N ω -nitro-D-arginine methyl ester (D-NAME, 50 mg · kg −1 ), impaired the inhibitory avoidance 2 with no change in the baseline values, thus suggesting an anxiolytic-like effect without locomotor impairment. All treatments with L-NAME were able to induce increased mean arterial pressure (MAP), measured indirectly through the animal’s tail. The treatment with L-NAME (5 and 10 mg · kg −1 ) failed to induce anxiolysis but significantly increased the MAP of the animals, which indicates that hypertension per se , did not underlie anxiolysis induced by L-NAME. L-Arginine, the precursor molecule for NO synthesis, facilitated the inhibitory avoidance and counteracted the L-NAME (50 mg · kg −1 )-induced anxiolysis. Neither previous treatment was able to change the escape behaviour. The results indicate that NO may underlie learned, but not innate, fear in the ETM. |
| Databáze: | OpenAIRE |
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