Figure 3.
Effects of 5-HT receptor agonists and antagonists on stimulus-evoked field potential responses. (A) 5-CT (10 μM) strongly reduced the stimulus-evoked synaptic field potential response in the superficial layers of the medial entorhinal cortex. Note that the antidromic response was not affected. After washout of 5-CT and following the application of the 5-HT1A-receptor antagonist WAY100635 a second application still reduced the response, but to a smaller extent (see also the summarizing histogram in Bc). (Ba) Histograms summarizing the lack of effect (CGS12066A, α-methyl-5-HT, 2-methyl-5-HT) and effects (5-CT, 8-OH-DPAT) of different 5-HT receptor agonists. (Bb) The 5-HT7-receptor antagonists ritanserin and clozapine (both applied at 100 μM) had no antagonistic effect, while the 5-HT1A-receptor antagonist, S-UH-301, reduced the serotonin-effect significantly. (Bc) The 5-HT1A-receptor antagonist WAY100635 reduced significantly the effect of 10 μM 5-CT. *Mean ratios significantly different from control (P<0.05).