Fig. 6. Application of the adenylate cyclase activator forskolin has little effect on most polyamine-evoked electro-olfactogram (EOG) responses, suggesting that the adenylate cyclase activation is not critical during the initial transduction of a polyamine stimulus. (A) Example responses elicited by glutamine, spermidine and TCA in an AFW background (left traces) or in the presence of 10 µmol l^–1 forskolin (right traces). (B) Summary changes in odor-evoked responses in the presence of forskolin normalized to the pre-drug treatment level. The magnitude of the taurocholic acid-evoked response was significantly reduced (t-test; P<0.05) but the L-glutamine-evoked response, while reduced, was not significantly smaller than the pre-forskolin exposure response level (t-test; P>0.05). Asterisks designate responses significantly reduced compared to the pre-forskolin exposure responses (paired t-test; P<0.05). Each odorant was tested on three preparations and values are means ± S.E.M. ns, non-significant. Abbreviations as in Fig. 1.