Amphioxus Hormone-Nerve Interaction

Immunorecognition of Estrogen and Androgen Receptors in the Nervous System and Hatschek's Pit of Amphioxus (Goog)
Article in Chinese but abstract in English. 

The results showed that the immuno recognition of estrogen and androgen receptors existed in the telencephalon and the middle and posterior part of midbrain.  Immunopositive substances (were) mostly located in the nucleus of nerve cells, with a few in the cytoplasm. 

The dorsal side and middle region of nerve tube also showed immunopositive reaction, and the immunopositive substances of estrogen and androgen receptors distributed in the nucleus, cytoplasm and nerve fibers of nerve cells. 

... immuno-recognition of estrogen and androgen receptors existed in the nucleus or the cytoplasm of epithelial cells (primitive gonadotrophic cells in Amphioxus) in the base part of Hatschek's pit at different stages of development. ... the immunorecognitive regions of the estrogen and androgen receptors in the brain and Hatschek's pit are similar to those of vertebrates. 

It suggests that sex steroid hormones exert feedback regulation on brain and Hatschek's pit ...