Summary
Rat brain cortex slices preincubated with 3H-5-hydroxytryptamine and superfused with physiological salt solution were stimulated electrically at a frequency of 3Hz.
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1.
The electrically evoked 3H-overflow was decreased by clonidine, noradrenaline and B-HT 920 in a concentration-dependent manner (negative logarithms of the IC30 values: 6.66, 6.55 and 4.40, respectively).
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2.
Phenylephrine 10−5M (which increased basal 3H-efflux) and methoxamine 10−4M decreased the impulse-evoked 3H-overflow by less than 25% whereas lower concentrations were ineffective.
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3.
Yohimbine produced a shift to the right of the concentration-response curves of noradrenaline (apparent pA2: 6.93) and clonidine (apparent pA2: 7.06) for their inhibitory effects on evoked 3H-overflow. Rauwolscine also shifted the concentration-response curve of noradrenaline to the right (apparent pA2: 7.29), whereas prazosin (10−6 and 3.2×10−6M) was ineffective in this respect.
These results suggest that the α-adrenoceptors on the serotoninergic nerve fibres belong to the α2-subtype
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This study was supported by a grant of the Deutsche Forschungsgemeinschaft
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Göthert, M., Huth, H. & Schlicker, E. Characterization of the receptor subtype involved in alpha-adrenoceptor-mediated modulation of serotonin release from rat brain cortex slices. Naunyn-Schmiedeberg's Arch. Pharmacol. 317, 199–203 (1981). https://doi.org/10.1007/BF00503816
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DOI: https://doi.org/10.1007/BF00503816