Abstract
Rat brain cortex slices preincubated with 3H-5-hydroxytryptamine and superfused with physiological salt solution were stimulated electrically at a frequency of 3 Hz. 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) 2. Phenylephrine 10-5 M (which increased basal 3H-efflux) and methoxamine 10-4 M decreased the impulse-evoked 3H-overflow by less than 25% whereas lower concentrations were ineffective. 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 x 10-6 M) was ineffective in this respect. These results suggest that the alpha-adrenoceptors on the serotoninergic nerve fibres belong to the alpha2-subtype.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
