There was no significant difference in the frequency of either spontaneous or inspiratory-related GABAergic IPSCs during a single α-Me-5-HT application at concentrations of 0.1 (n = 6), 1 (n = 10), or 5 μM (n = 6). Similarly, the decrease of the frequency of spontaneous GABAergic IPSCs 2 min after multiple applications of α-Me-5-HT was not found to be concentration dependent, (n = 6, 10, and 6 CVNs at concentrations of .1, 1, and 5 μM, respectively). However, the inhibition of frequency of fictive inspiratory-related GABAergic IPSCs 2 min after multiple applications of α-Me-5-HT at a concentration of 5 μM (n = 6) was significantly lower (p < 0.05) than the responses at a concentration of 0.1 μM (n = 6) but not significantly different from the responses at a concentration of 1 μM (n = 10).