Fig. 7.
Activation of P2X7 receptors promotes nerve terminal destaining associated with transmitter release at the neuromuscular junction. Nerve terminals were loaded with FM1–43 or RH414 and transferred to the microscope stage. Terminals were visualized, using a ND25 filter at all times, at t= 0 (a, c, e) and every 5 min untilt = 30 min (b, d, f). Control preparations were repeatedly imaged and showed modest photobleaching (a, b). In an identical experiment but with 30 μm BzATP added at t = 0 (c, d), terminals destained by ∼50%, over 30 min. In a repeat experiment in which the preparation was preincubated with 100 μm oxidized ATP (e, f) or 1 μm Brilliant Blue G (g, h) before and during BzATP addition, BzATP-mediated destaining was prevented and terminals again demonstrated some photobleaching comparable with control over 30 min.