Enhanced retention in the passive-avoidance task by 5-HT(1A) receptor blockade is not associated with increased activity of the central nucleus of the amygdala.
The effect of blockade of 5-HT1A receptors was investigated on (1). retention in a mildly aversive passive-avoidance task, and (2). spontaneous single-unit activity of central nucleus of the amygdala (CeA) neurons, a brain site implicated in modulation of retention. Systemic administration of the selective 5-HT1A antagonist NAN-190 immediately after training markedly-and dose-dependently-facilitated retention in the passive-avoidance task; enhanced retention was time-dependent and was not attributable to variations in wattages of shock received by animals. Systemic administration of NAN-190 had mixed effects on spontaneous single-unit activity of CeA neurons recorded extracellularly in vivo; microiontophoretic application of 5-HT, in contrast, consistently and potently suppressed CeA activity. The present findings-that 5-HT1A receptor blockade by NAN-190 (1). enhances retention in the passive-avoidance task, and (2). does not consistently increase spontaneous neuronal activity of the CeA-provide evidence that a serotonergic system tonically inhibits modulation of retention in the passive-avoidance task through activation of the 5-HT1A receptor subtype at brain sites located outside the CeA.
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- Serotonin Antagonists
- Serotonin 5-HT1 Receptor Antagonists
- Retention, Psychology
- Receptor, Serotonin, 5-HT1A
- Rats, Long-Evans
- Rats
- Random Allocation
- Piperazines
- Neurology & Neurosurgery
- Male
Citation
Published In
DOI
ISSN
Publication Date
Volume
Issue
Start / End Page
Location
Related Subject Headings
- Serotonin Antagonists
- Serotonin 5-HT1 Receptor Antagonists
- Retention, Psychology
- Receptor, Serotonin, 5-HT1A
- Rats, Long-Evans
- Rats
- Random Allocation
- Piperazines
- Neurology & Neurosurgery
- Male