Figure 2. In the absence of α₁-adrenoceptor stimulation, 9% CO₂ does not change firing rate of spontaneously active serotonergic neurons in control mice.

A, Time-course of a representative experiment. Phenylephrine was omitted from ACSF containing synaptic blockers. Inset shows the recorded action current. B, Distribution of responses to 9% CO₂ for all recorded neurons.