Fig. 2.

Agonist-induced Ca²⁺ efflux from TRPV1 vesicles. (a) Fura-2 excitation spectra measured before (dashed line) and immediately after (solid line) application of 50 nM resiniferotoxin (RTX) to the cuvette containing TRPV1 vesicles loaded with 5 mM internal Ca²⁺. Ionomycin (2 μM) induced changes represented by the small-dashed line. (b) The same experiment with protein-free vesicles prepared identically but without TRPV1 reveals no release of Ca²⁺ by RTX (n = 6). (c) Image of TRPV1 vesicles.