Fig. 3.

Somatostatin acts at presynaptic receptors.A shows EACs recorded at −70 mV in the presence of 2 mm Mg²⁺, in the presence of 2 mmMg²⁺ + 10 μm CNQX, after replacement of Mg²⁺ by 10 μm glycine, and after addition of 50 μm AP5. B shows the inhibition of EACs by somatostatin in a different microisland neuron in the presence of 2 mm Mg²⁺ (top traces) and after replacement of Mg²⁺ by 10 μm glycine (bottom traces). Currents were obtained before, during, and after the application of 1 μm somatostatin.C, Currents evoked by 100 μm glutamate at −70 mV in a mass culture neuron in the presence of 1 μmsomatostatin, as well as before and after application of the peptide.