BRADYKININ AND CAPSAICIN STIMULATE CYCLIC-GMP PRODUCTION IN CULTURED RAT DORSAL-ROOT GANGLION NEURONS VIA A NITROSYL INTERMEDIATE

Dorsal root ganglion (DRG) neurons express receptors for bradykinin an d capsaicin, both algesic substances. Administration of bradykinin or capsaicin to neurons cultured from embryonic rat DRG stimulated the pr oduction of cyclic GMP but did not affect the production of cyclic GMP in nonneuronal DRG cultures. Bradykinin-evoked cyclic GMP production was mediated by B2 receptors and was unaltered by indomethacin. Both b radykinin- and capsaicin-stimulated cyclic GMP production required Ca2 + and was inhibited by methylene blue. Furthermore, methylene blue att enuated basal cyclic GMP production in DRG neurons, suggesting tonic c yclic GMP production in these cells. L-N-G-monomethyl arginine inhibit ed both bradykinin- and capsaicin-stimulated cyclic GMP production as well as basal cyclic GMP production. These findings suggest the involv ement of a nitrosyl compound in bradykinin- and capsaicin-stimulated c yclic GMP production and in tonic cyclic GMP production in DRG neurons . (C) 1993 Wiley-Liss, Inc.