Effects of CMS on ipsapirone-induced inhibition of the firing of DRN 5-HT neurons. Comparison between GR-i and wild-type mice. Experiments were performed on the day immediately after a 4 week exposure to mild stress or nonstress conditions. A, Integrated firing rate histograms (in spikes per 10 sec) showing the inhibitory effect of increasing concentrations of ipsapirone on the electrical activity of a DRN 5-HT neuron in a control, unstressed, and a stressed wild-type mouse. B, Concentration-response curves of ipsapirone-induced inhibition of the firing of DRN 5-HT neurons in wild-type mice. Each point is the mean ± SEM of data obtained from 22 and 9 individual cells in unstressed and stressed mice, respectively. The dotted lines illustrate the EC50 values of ipsapirone (abscissa) in both groups. C, Integrated firing rate histograms (in spikes per 10 sec) showing the inhibitory effect of increasing concentrations of ipsapirone on the electrical activity of a DRN 5-HT neuron in a control, unstressed, and a stressed GR-i mouse. D, Concentration-response curves of ipsapirone-induced inhibition of the firing of DRN 5-HT neurons in GR-i mice. Each point is the mean ± SEM of data obtained from 16 and 10 individual cells in unstressed and stressed GR-i mice, respectively. The dotted lines illustrate the EC50 values of ipsapirone (abscissa) in unstressed and stressed GR-i mice. *p < 0.05, compared with corresponding values in control mice.
