Archives

  • 2018-07
  • 2018-10
  • 2018-11
  • 2019-04
  • 2019-05
  • 2019-06
  • 2019-07
  • 2019-08
  • 2019-09
  • 2019-10
  • 2019-11
  • 2019-12
  • 2020-01
  • 2020-02
  • 2020-03
  • 2020-04
  • 2020-05
  • 2020-06
  • 2020-07
  • 2020-08
  • 2020-09
  • 2020-10
  • 2020-11
  • 2020-12
  • 2021-01
  • 2021-02
  • 2021-03
  • 2021-04
  • 2021-05
  • 2021-06
  • 2021-07
  • 2021-08
  • 2021-09
  • 2021-10
  • 2021-11
  • 2021-12
  • 2022-01
  • 2022-02
  • 2022-03
  • 2022-04
  • 2022-05
  • 2022-06
  • 2022-07
  • 2022-08
  • 2022-09
  • 2022-10
  • 2022-11
  • 2022-12
  • 2023-01
  • 2023-02
  • 2023-03
  • 2023-04
  • 2023-05
  • 2023-06
  • 2023-08
  • 2023-09
  • 2023-10
  • 2023-11
  • 2023-12
  • 2024-01
  • 2024-02
  • 2024-03
  • br Abbreviations br Acknowledgements This work was supported

    2022-12-02


    Abbreviations
    Acknowledgements This work was supported by grants from the National Institutes of Health (R01GM114168) and the Office of Naval Research (N000141210773) awarded to J.C·H and National Cancer Institute (5P30CA16059) Cancer Center Support Grant in support of Massey Cancer Center Proteomics Resource.
    Introduction The actions of locally produced sex steroids in the amyloid have come to the forefront in neuroethology research, because these steroids provide a mechanistic pathway to explain rapid and transient changes in neural activity and behavior (Remage-Healey, 2012). A first step towards understanding the function of locally produced steroids in the brain is to determine where these steroids are produced, i.e. where in the brain steroidogenic enzymes are expressed. Aromatase is a steroidogenic enzyme in the cytochrome P450 superfamily that enables the conversion of the aromatizable androgens, testosterone and androstenedione, into the bioactive estrogens, estradiol and estrone, respectively (Naftolin et al., 1974). Aromatase activity is believed to play an important role in vertebrate physiology and behavior, because its expression has been conserved across vertebrate lineages (Castro et al., 2005). Teleosts are unique among vertebrates in possessing two distinct aromatase genes, termed cyp19a1a and cyp19a1b, that are hypothesized to have arisen following the whole genome duplication event in the common ancestor of teleosts (Pellegrini et al., 2005). Over time, the cyp19a1a and cyp19a1b gene sequences diverged and their expression was restricted predominantly to the ovary and brain, respectively (reviewed in Diotel et al., 2010). Identifying the expression pattern of brain aromatase can help us to understand how its activity affects neural circuits and behaviors. To date, the mRNA expression pattern of brain aromatase in teleosts has been identified in several species including killifish Fundulus heteroclitus (Dong and Willett, 2008), plainfin midshipman Porichthys notatus (Forlano et al., 2001), zebrafish Danio rerio (Goto-Kazeto et al., 2004; Menuet et al., 2005), guppies Poecilia reticulata (Hallgren, 2009), the Japanese eel Anguilla japonica (Jeng et al., 2012), rainbow trout Oncorhynchus mykiss (Menuet et al., 2003), the Asian stinging catfish Heteropneustes fossilis (Mishra and Chaube, 2016), and pejerrey Odontesthes bonariensis (Strobl-Mazzulla et al., 2008). Among these teleosts there is a high degree of regional conservation in the neural expression pattern of aromatase, with highest levels seen in forebrain regions, most notably the peripheral layer of the telencephalon, the forebrain ventricles, preoptic area, and the ventral hypothalamus. Much lower expression levels have been documented in the midbrain and hindbrain regions with many differences observed between species. The neural expression pattern of aromatase can be informative in identifying potential behaviors that might be under local control by estrogen, as well as provide insights into potential mechanisms underlying individual differences in these behaviors. For example, in the plainfin midshipman fish aromatase is expressed in forebrain regions involved in the vocal-acoustic circuit used for call production (Forlano and Bass, 2011). Differences in the level of aromatase expression have been identified between males and females, as well as between male reproductive morphs, and are hypothesized to underlie individual differences in calling behavior during social interactions (Forlano and Bass, 2005). It is therefore interesting to extend the study of aromatase in the brain to other systems in which the neural circuitry underlying signal production has been well characterized to see if aromatase expression might also be important for regulating local estrogen production involved in other signaling systems. Apteronotus leptorhynchus is a South American weakly electric fish. These fish use active electrosensation as their main sensory modality for both navigation in their environment (Heiligenberg and Bastian, 1986) and social communication (Hopkins, 1974; reviewed in Lorenzo et al., 2006). They use emissions of a quasi-sinusoidal electric organ discharge (EOD) signal to create an electric field around the body. Electroreceptors that line the body surface detect objects in the environment and the EODs of conspecifics via distortions created in the electric field. In aggressive and courtship interactions, fish produce slow and rapid frequency modulations of their EOD, called the jamming avoidance response (JAR) and chirps, respectively (Bullock et al., 1972a, Bullock et al., 1972b; Zakon et al., 2002).