title: Inhibition of nitric oxide synthase reduces ultrasonic vocalizations of rat pups.
abstract: The present study investigated the effects of drugs acting on the brain nitric oxide pathway on ultrasonic vocalizations, body temperature and locomotion in 7-8-day-old rat pups. Both a selective neuronal nitric oxide synthase (NOS) inhibitor (7-nitroindazole) and a non-selective NOS inhibitor (nitro-L-arginine-methyl ester, L-NAME) decreased the number of ultrasonic vocalizations in a dose-dependent manner. The non-selective NOS inhibitor, L-NAME, suppressed not only ultrasonic vocalizations but also locomotion. The inactive isomer of the NOS inhibitor, nitro-D-arginine-methyl ester (D-NAME), and the biological precursor of nitric oxide, L-arginine, had no effect on ultrasonic vocalizations or locomotion. These data indicate that drugs suppressing nitric oxide synthesis produced an anxiolytic effect in rat pups. However, only the selective NOS inhibitor, 7-nitroindazole, was 'anxioselective', i.e., reduced ultrasonic vocalizations without causing sedation. Increased synthesis of nitric oxide in the brain had no apparent behavioral effect in this model.
authors.affiliation: Department of Psychology, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Podhorna
authors.forename: R E
authors.initials: RE
authors.lastname: Brown
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D014151:Anti-Anxiety Agents / Q000494:pharmacology; D001120:Arginine / Q000494:pharmacology; D001831:Body Temperature / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D007191:Indazoles / Q000494:pharmacology; D009043:Motor Activity / Q000187:drug effects; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D051381:Rats; D020318:Rats, Long-Evans; D013237:Stereoisomerism; D014465:Ultrasonics; D014828:Vocalization, Animal / Q000187:drug effects*
chemical_list: D014151:Anti-Anxiety Agents; D004791:Enzyme Inhibitors; D007191:Indazoles; D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase; C080122:7-nitroindazole; D019331:NG-Nitroarginine Methyl Ester