W. Sommer et al., Local 5,7-dihydroxytryptamine lesions of rat amygdala: Release of punisheddrinking, unaffected plus-maze behavior and ethanol consumption, NEUROPSYCH, 24(4), 2001, pp. 430-440
several serotonergic drugs are effective for anxiety disorders but underlyi
ng mechanisms are unclear, adn findings in experimental animals are difficu
lt to reconcile with human data. It has been proposed that differential eff
ects of serotonin within specific anatomical systems may account for these
difficulties, and the amygdala has been suggested as one of the structures
involved. To examine this hypothesis, the neurotoxin 5,7-dihydroxytryptamin
e was administered locally in rat amygdala. Within the amygdala, serotonin
was depleted by approximately 80%, with other transmitters unaffected and s
erotonin transporter labelling was decreased by approximately 85%. Cortical
areas near the lesion site were also affected, although to a lesser degree
. Other forebrain areas were unaffected. Lesion resulted in a specific anti
-conflict effect in a punished drinking test, but did not influence elevate
d plus-maze behavior (under basline conditions and after restraint stress),
locomotor activity or ethanol intake. These data suggest that the punished
drinking test and the elevated plus-maze may activate different components
of fear circuitry, and that the serotonergic input to the amygdala specifi
cally participates in fear-related behavioral suppression mediated by this
structure. (C) 2001 American College of Neuropsychopharmacology. Published
by Elsevier Science Inc.