Fig. 7.
Afferent synapses in AON are facilitating and unmodulated by GABAB receptors. A: the paired pulse ratio of voltage clamp responses to LOT stimulation is plotted as a function in the interstimulus interval (ISI). Black circles and gray lines show individual neurons; open triangles and black lines show the average response. LOT synapses onto AON principal neurons were facilitating for ISIs ranging from 50–200 ms. Inset shows an example response to paired pulse stimulation. B: bath application of baclofen, followed by CGP55845, did not change the paired pulse ratio of LOT stimulation. C: bath application of baclofen reversibly reduced the EPSC amplitude by almost 50% with a potassium-based pipette solution (left), whereas it irreversibly reduced the EPSC amplitude by <25% with a cesium-based electrode (right). D: bath application of baclofen caused a reversible shift in the holding current with a potassium-based pipette solution (left) that was abolished with a cesium-based solution (right), suggesting activation of GABAB receptors in the recorded (postsynaptic) neuron. Grayscale code for pharmacological condition is shown in C and D. *P < 0.05.