Fig. 3.

Excitatory synaptic transmission mediated by nicotinic receptors. A, An action potential was generated by electrical stimulation lateral to the SpL (left). Stimulation was at 0.05 Hz (450 μA, 300 μsec). The nicotinic receptor antagonist DHβE (30 μm) blocked the action potential but did not completely block the EPSP (right). B, In another SpL neuron, an antagonist cocktail containing AP-5 (50 μm), DNQX (40 μm), bicuculline (10 μm), and atropine (1 μm) was given to isolate the nicotinic response. The isolated nicotinic EPSP increased in amplitude with increasing stimulation intensity and, at 700 μA, 500 μsec (left), was sufficient to generate an action potential. DHβE (30 μm) completely blocked the action potential and EPSP (right).