Fig. 9. Polyamine stimulation of the olfactory epithelium resulted in a modest, non-significant, increase in activity-dependent labeling of OSNs compared to the level of labeling noted during control stimulation with AGB alone or the robust stimulation elicited by glutamine. Each odorant was tested on a minimum of two olfactory rosettes from two different fish. A minimum of six areas of interest from three planes of section were sampled for each fish. Asterisks designate significantly greater labeled epithelium than in the AGB control preparations (one way ANOVA, post hoc t-test; P<0.05). Values are means ± S.E.M. Abbreviations as in Fig. 1.