Figure 9. Effect of naloxone on recurrent inhibition of bladder Aδ reflexes.

Bladder Aδ reflexes recorded with the bladder filled (same experiment as Fig. 8). Each horizontal row of single traces illustrates a conditioning trial with reflex responses taken before and at indicated times after conditioning stimulation of the contralateral BPN (20 s, 20 Hz). Conditioning trials were performed before (A), 17 min (B) and 65 min (C) after naloxone (0.1 mg kg⁻¹i.v.) The test stimulation intensity was reduced in B (from 4 to 2 × threshold for the Aδ reflex) to obtain an Aδ reflex of about the same size as in A, yet the recurrent inhibition was virtually abolished.