Figure 4.

Effects of intra-raphe microinjection of GABA_A receptor ligands on SCN 5-HT release. A, Injection of the GABA_A agonist bicuculline (BICUC) into the DRN (n = 5) and MRN (n = 5) significantly stimulated 5-HT release. B, Injection of the GABA_A antagonist muscimol (MUSC) into the DRN (n = 6) and MRN (n = 5) suppressed 5-HT release, with the duration of this effect being greater in the DRN. C, The stimulatory effect of intra-DRN injection of bicuculline is abolished by intra-DRN pretreatment with DR4004 (n = 5 per group). For all graphs, ^ap < 0.05 versus pretreatment baseline levels; ^*p < 0.05 versus complementary site-drug treatment for a given time point. Data are mean ± SEM. Differences in bicuculline potency between the two experiments were caused primarily by the greater variability in response in A and possibly differences in drug potency between different lots that were used.