Figure 2. Synaptic and cellular currents in CA3 pyramidal cells are unaffected by H₃ receptor activation.

A, EPSCs were recorded in standard ACSF in the absence of drugs, after kainate application, and activation of H₃ receptors. Activation of kainate receptors (middle trace) shows the strong increase in number and amplitude of EPSCs typical during gamma oscillations. Activation of H₃ receptors leaves EPSCs unaffected. Summary histogram is below. B, IPSCs were recorded in standard ACSF in the absence of drugs, after kainate application, and activation of H₃ receptors. Activation of kainate receptors (middle trace) shows the strong increase in number and amplitude of IPSCs typical during gamma oscillations. Activation of H₃ receptors leaves IPSCs unaffected. GABA_A receptor block (lowest trace) removes the PSCs observed before and confirms their inhibitory nature. Summary histogram is below. C, example trace of cellular current recording (left; V_h=−60 mV). Observe a slowly developing inward current in response to kainate but no additional response to RAMH. The summary diagram (right) quantifies the cellular current experiments.