Selective 5-HT1A receptor agonist, 8-OH-DPAT, locally administered into the dorsal raphe nucleus increased extracellular acetylcholine concentrations in the medial prefrontal cortex of conscious rats.

The effects of a selective 5-hydroxytryptamine (5-HT)1A receptor agonist, 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT), directly administered into the dorsal raphe nucleus (DR) on acetylcholine (ACh) release in the medial prefrontal cortex (mPFC) of freely moving rats were investigated by using a microdialysis technique. 8-OH-DPAT (1.0 and 5.0 micrograms) administered into DR significantly increased extracellular ACh concentrations in mPFC in a dose-dependent manner with a maximal increase to 215% and 237% of basal level, respectively, whereas a 0.1 microgram dose of this drug failed to exert such an increase. The present study suggests that the stimulation of somatodendritic 5-HT1A autoreceptors in DR is involved in an enhancement in ACh release in mPFC.