Figure 6. Suramin preferentially blocks the excitatory synaptic response evoked by chemoreceptor stimulation.

Whole-cell recording of an NTS neurone responding to activation of peripheral chemoreceptors and receiving a convergent input from pharyngo-oesophageal receptors (PO). Note that the convergent PO-evoked input was unaffected. This cell had an input resistance of 220 MΩ and showed no change in this variable, resting membrane potential or on-going firing rate after suramin. Suramin (100 μM) was applied topically to recorded neurones via a perfusable well (see Paton, 1998); the absolute concentration at the neurone is unknown but <100 μM.