PT - JOURNAL ARTICLE AU - Marco Colasanti AU - Giorgio Venturini AU - Angelo Merante AU - Giovanni Musci AU - Giuliana M. Lauro TI - Nitric Oxide Involvement in <em>Hydra vulgaris</em> Very Primitive Olfactory-Like System AID - 10.1523/JNEUROSCI.17-01-00493.1997 DP - 1997 Jan 01 TA - The Journal of Neuroscience PG - 493--499 VI - 17 IP - 1 4099 - http://www.jneurosci.org/content/17/1/493.short 4100 - http://www.jneurosci.org/content/17/1/493.full SO - J. Neurosci.1997 Jan 01; 17 AB - Hydra feeding response is a very primitive olfactory-like behavior present in a multicellular organism. We investigated the role of nitric oxide (NO) in the induction and control of hydra feeding response. Under basal conditions, hydra specimens produce detectable amounts of nitrite (NO2−), the breakdown product of NO. When hydra were incubated with reduced glutathione (GSH), the typical activator of feeding response, an increase of basal NO production was observed. This effect was inhibited by glutamic or α-aminoadipic acids, two GSH antagonists, which block GSH-induced feeding response, and by the NO synthase (NOS) inhibitor l-NAME. Moreover, we found that hydra possess a calcium-dependent (but calmodulin-independent) NOS isoform. By using exogenous NO donors and NOS inhibitors, we demonstrated that NO stimulus can participate both in triggering tentacular movements and in recruiting neighbor tentacles during hydra feeding response. By using dbt2-cGMP, an analog to cGMP, we observed that the NO effect was independent of cGMP pathway. Our results strongly implicate NO involvement in hydra very primitive feeding behavior, thus confirming its preservation throughout evolution.