Decreased spontaneous motor activity and startle response in nitric oxide synthase inhibitor-treated rats
In the central nervous system, nitric oxide has been proposed to be a retrograde messenger mediating learning and synaptic plasticity. Since only pretraining injections of nitric oxide synthesis inhibitors were shown to impair learning, we examined the possibility that systemic administration of these inhibitors might influence some non-specific aspects related to the organism's general psychophysiological status. Intraperitoneal administration of NG-nitro-L-arginine methyl ester (30 or 100 mg/kg) 60 min pre-test to adult rats resulted in: (i) altered exploratory pattern and reduced locomotion in a novel environment; (ii) reduced startle response to either acoustic or electric stimuli; and (iii) cardiovascular alterations. In addition, intracerebroventricular administration of N-nitro-L-arginine (10 microliters of a 10 mM solution) diminished the acoustic startle response. Specificity of these effects through nitric oxide was supported by the ability of the nitric oxide precursor, L-arginine, to prevent the inhibitors actions. These findings indicate that nitric oxide inhibitors interfere with the general psychophysiological status of the organism.
Keywords: Acoustic Stimulation ; Amino Acid Oxidoreductases/ antagonists & inhibitors ; Analysis of Variance ; Animals ; Arginine/administration & dosage/ analogs & derivatives/pharmacology ; Blood Pressure/drug effects ; Electric Stimulation ; Heart Rate/drug effects ; Injections ; Intraperitoneal ; Injections ; Intraventricular ; Male ; Motor Activity/ drug effects ; NG-Nitroarginine Methyl Ester ; Nitric Oxide/ antagonists & inhibitors ; Nitric Oxide Synthase ; Nitroarginine ; Rats ; Rats ; Wistar
Author address: Psychobiology Research Group, Cajal Institute, CSIC, Madrid, Spain.
Record created on 2007-01-18, modified on 2016-08-08