Estrogenic Modulation of Retinal Sensitivity in Reproductive Female Túngara Frogs

Abstract Although mate searching behavior in female túngara frogs (Physalaemus pustulosus) is nocturnal and largely mediated by acoustic cues, male signaling includes visual cues produced by the vocal sac. To compensate for these low light conditions, visual sensitivity in females is modulated when...

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Bibliographic Details
Published in:Integrative and comparative biology 2021-07, Vol.61 (1), p.231-239
Main Authors: Leslie, Caitlin E, Walkowski, Whitney, Rosencrans, Robert F, Gordon, William C, Bazan, Nicolas G, Ryan, Michael J, Farris, Hamilton E
Format: Article
Language:English
Subjects:
Animals
Anura - physiology
Chorionic Gonadotropin - pharmacology
Estradiol - pharmacology
Fadrozole - pharmacology
Female
Male
Medicin och hälsovetenskap
Reproduction
Retina - drug effects
Retina - physiology
Sexual Behavior, Animal
Vision, Ocular
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Summary:Abstract Although mate searching behavior in female túngara frogs (Physalaemus pustulosus) is nocturnal and largely mediated by acoustic cues, male signaling includes visual cues produced by the vocal sac. To compensate for these low light conditions, visual sensitivity in females is modulated when they are in a reproductive state, as retinal thresholds are decreased. This study tested whether estradiol (E2) plays a role in this modulation. Female túngara frogs were injected with either human chorionic gonadotropin (hCG) or a combination of hCG and fadrozole. hCG induces a reproductive state and increases retinal sensitivity, while fadrozole is an aromatase inhibitor that blocks hCG-induced E2 synthesis. In an analysis of scotopic electroretinograms (ERGs), hCG treatment lowered the threshold for eliciting a b-wave response, whereas the addition of fadrozole abolished this effect, matching thresholds in non-reproductive saline-injected controls. This suggests that blocking E2 synthesis blocked the hCG-mediated reproductive modulation of retinal sensitivity. By implicating E2 in control of retinal sensitivity, our data add to growing evidence that the targets of gonadal steroid feedback loops include sensory receptor organs, where stimulus sensitivity may be modulated, rather than more central brain nuclei, where modulation may affect mechanisms involved in motivation.
ISSN:1540-7063
1557-7023
1557-7023
DOI:10.1093/icb/icab032