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. 2001 Mar 1;531(Pt 2):425–435. doi: 10.1111/j.1469-7793.2001.0425i.x

Figure 6. The presynaptic inhibition induced by 5-HT increases action potential firing frequency.

Figure 6

In DMV neurones in which 5-HT itself had no effect on evoked IPSC amplitude, stimulation of the NTS to evoke an inhibitory postsynaptic potential (*) decreased the number of action potentials fired in response to injection of a depolarizing current pulse (A). 5-HT itself did not alter the number of action potentials fired in the presence of NTS stimulation (B), but increased the number of action potentials following preincubation with forskolin (C). Holding potential: -55 mV. The histogram (D) summarizes the alterations in the number of action potentials fired. Note that following stimulation of the NTS the number of action potentials fired decreased significantly but perfusion with 5-HT following preincubation with forskolin not only abolished this decrease, but resulted in an increase in action potential firing rate compared with control. *P < 0.05vs. control.