Fig 5. Cyclen impeded spermine-induced olfactory and behavioral responses.
(A) Cyclen treatment (10−5 M) reduced the EOG response magnitude to spermine (10−5 M) but not to 3kPZS (10−7 M), spermidine (10−5 M), or L-arginine (10−5 M). EOG responses were blank-subtracted and normalized to the amplitude of the responses to 10−5 M L-arginine (mean ± SEM, n = 5). The difference in responses for each stimulus before (gray) and during (white) exposure of the naris to cyclen was evaluated with a paired t test. (B) Ovulatory female sea lamprey behavioral responses to spermine and 3kPZS (positive control) in the absence and presence of 10−12 M cyclen (cyclen background) in a two-choice maze assay (S2 Fig). The effect of cyclen was reversible because the attraction to spermine was rescued when cyclen application ceased. For the definition of the index of preference, see Materials and methods. A positive index value indicates attraction, and a negative index value indicates repulsion. Significance was evaluated using a Wilcoxon signed-rank test. The number in the parentheses indicates the number of test subjects spending more time in the experimental channel out of the total sample size. *p < 0.05, **p < 0.01. Underlying data are available in S1 Data. EOG, electro-olfactogram; n.s., not significant; 3kPZS, 3-keto petromyzonol sulfate.