Figure 2.

Effects of nociceptin, [Tyr¹⁴]-nociceptin ([Tyr¹⁴]-N) and [des-Phe¹]-nociceptin ([des-Phe¹]-N) on (A) the electrically evoked tritium overflow from superfused mouse brain cortex slices preincubated with [³H]-noradrenaline and (B) the specific [³H]-nociceptin binding to mouse brain cortex membranes. (A) The slices were superfused with medium containing desipramine 1 μM, rauwolscine 1 μM plus naloxone 10 μM throughout superfusion and nociceptin or one of the chemically related peptides from 62 min of superfusion onward. Tritium overflow was evoked by two 2-min periods of electrical stimulation (0.3 Hz, 50 mA, 2 ms), after 40 and 90 min of superfusion (S₁, S₂), and the ratio of the overflow evoked by S₂ over that evoked by S₁ was determined. (B) Membranes were incubated for 60 min with 0.5 nM [³H]-nociceptin and increasing concentrations of the competitor. The results, which represent means±s.e.m. of four superfusion experiments (A) and 4–6 binding experiments in triplicate (B), are given as per cent of controls (controls not shown); for some data points, s.e.m. is contained within the symbol.