Learning And Memory
The effect of blockade of S-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 S-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 S-HT, in contrast, consistently and potently suppressed CeA activity. The present findings-that S-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 S-HT1A receptor subtype at brain sites located outside the CeA.
Allen M. Schneider; Emily Wilkins , '01; Aaron Alexander Firestone , '01; E. Carr Everbach; J. C. Naylor; and Peter E. Simson , '78.
"Enhanced Retention In The Passive-Avoidance Task By 5-HT1A Receptor Blockade Is Not Associated With Increased Activity Of The Central Nucleus Of The Amygdala".
Learning And Memory.