Intra-amygdaloid microinjection of neuropeptide glutamic acid-isoleucine induces anxiety-like behavior

• Published in: Neuroreport Vol. 22; no. 2; p. 83
• Main Authors: Gastón, Soledad, Gargiulo, Pascual A, Bregonzio, Claudia, Baiardi, Gustavo
• Format: Journal Article
• Language: English
• Published: England 26.01.2011
• Subjects: Amygdala - drug effects; Animals; Anxiety - blood; Anxiety - chemically induced; Behavior, Animal - drug effects; Corticosterone - blood; Male; Microinjections; Motor Activity - drug effects; Oligopeptides - administration & dosage; Rats; Rats, Wistar
• ISSN: 1473-558X
• DOI: 10.1097/WNR.0b013e328342b9ef

The amygdaloid complex is involved in anxiety or fear responses to stressful stimuli. In this study the effect of neuropeptide-EI on anxiety-like behavior and its influence on adrenocortical function was tested in male Wistar rats that were injected bilaterally in the basolateral amygdala with neuropeptide-EI (1 μg/1 μl) or artificial cerebrospinal fluid and placed on the plus maze. The plasma corticosterone levels were analyzed in controls and plus-maze exposed animals. Neuropeptide-EI in the basolateral amygdala significantly decreased the time spent in open arms but had no effect on locomotor activity, showing an anxiogenic effect. However, neuropeptide administration did not change serum corticosterone levels compared with vehicle controls. Our results suggest that the anxiogenic effect of neuropeptide-EI could be independent of the hypothalamic-pituitary-adrenocortical system response.