Fj. Bosker et al., POSTSYNAPTIC 5-HT1A RECEPTORS MEDIATE 5-HYDROXYTRYPTAMINE RELEASE IN THE AMYGDALA THROUGH A FEEDBACK TO THE CAUDAL LINEAR RAPHE, European journal of pharmacology, 333(2-3), 1997, pp. 147-157
Using brain microdialysis, it was demonstrated that the release of 5-h
ydroxytryptamine (5-HT) in the central nucleus of the amygdala is unde
r inhibitory control of somatodendritic and postsynaptic 5-HT1A recept
ors. Systemic administration of flesinoxan, a selective 5-HT1A recepto
r agonist, significantly reduced the extracellular levels of 5-HT in t
he central nucleus of the amygdala. This effect could be completely an
tagonized by the 5-HT1A receptor antagonist oxyphenyl)-1-piperazinyl)-
N-(2-pyridyl)cyclohexane carboxamine trihydrochloride (WAY 100635). Lo
cal administration of these compounds by reversed microdialysis into t
he raphe nuclei revealed that extracellular 5-HT levels in the central
nucleus of the amygdala can be regulated through 5-HT1A receptors in
the caudal linear raphe nucleus, but not in the dorsal and median raph
e nuclei. Interestingly, administration of flesinoxan into the central
nucleus of the amygdala also decreased dialysate 5-HT levels both loc
ally and in the caudal linear raphe nucleus. The former effect could b
e blocked by pretreatment with WAY 100635 when applied into the centra
l nucleus of the amygdala, but not when applied into the caudal linear
raphe nucleus. These data provide circumstantial evidence for the exi
stence of a 5-HT1A receptor mediated feedback loop from the central nu
cleus of the amygdala to the caudal linear raphe nucleus. (C) 1997 Els
evier Science B.V.