Fig. 9.

Effects of 5-HT₃ receptor on afferent-evoked synaptic responses recorded from single cells in the whole-cell patch-clamp configuration. A,C, The 5-HT₃ receptor agonist M-109 (100 μm) reduces both glutamatergic (A) and GABAergic (C) electrically evoked synaptic responses. Recordings were made from a P30 pyramidal cell (A) and a P36 stellate cell (C). B, D, The effect was suppressed by the 5-HT₃ receptor antagonist ICS 205–930 (10–20 nm; gray traces). Recordings from a P16 (B) and a P8 (D) pyramidal cell. All traces represent the averages of at least 20 recordings. Evoked IPSCs (C,D) were recorded in the presence of 20 μmd-APV and 50 μm CNQX. The last panel in each row shows the time course of the peak PSC amplitude measured every 20 sec.