Figure 2.

Agonist activity and photolabelling by iodoazidococaine (IAC)

A, IAC reduced I_K evoked by voltage pulses as in Fig. 1. B, time course of modulation of I_K while drug was added and removed (the time of drug application is indicated by the bar). Values plotted were normalized to predrug control I_K. Peak I_K was reduced by 100 μm pentazocine and 100 μm IAC. Three minutes after return to control solution I_K partly recovered in the terminal exposed to pentazocine but not in the terminal exposed to IAC. C, SDS-polyacrylamide gel electrophoresis was performed on homogenized neurohypophysis after photolabelling with [¹²⁵I]IAC. Phosphorimaging revealed labelled proteins. A band at 26 kDa was labelled (left), and the labelling of this band was blocked by 100 μm SKF10047 (right).