Figure 7.

The potentiating action of NGF on P2X₃ receptor-mediated responses does not depend on CGRP. A, Examples of currents induced by α,β-meATP in TG neurons grown in control condition, in the presence of NGF (50 ng/ml, 24 h), in the presence of CGRP receptor antagonist BIBN4096BS (BIBN; 50 ng/ml, 24 h), or with NGF plus BIBN4096BS (24 h). B, Somatic size distribution of TG neurons immunostained with TrkA receptor antibody (filled columns) and labeled with CGRP-RITC (open columns) to investigate colocalization of NGF and CGRP receptors (filled, cross-hatched columns). Data are from ∼1000 cells (n = 3 independent experiments). IR, Immunoreactivity. C, Example of patch-clamp traces showing that CGRP application (1 μm, 1 h) to anti-NGF antibody-treated neurons increases α,β-meATP responses and accelerates recovery from desensitization (30 s interval between twin pulses). D, CGRP (1 μm, 1 h) potentiates α,β-meATP-evoked currents in control condition (n = 19; *p < 0.0001) and after anti-NGF treatment (n = 18; *p < 0.0001).