Amphioxus Neuropeptides

Cross references:    Amphioxus Oxytocin

Immunohistochemical investigation of neuropeptides in the central nervous system of the amphioxus
Only abstract available online.  The university through which I normally access PDFs that are behind paywalls was unable to give me access to this, and Springerlink wanted $35.  Fortunately, the university did have the hard copy. 
The immunohistochemical localization of nine different neuropeptides was studied in the central nervous system of the amphioxus, Branchiostoma belcheri. ...
Perikarya immunoreactive for arginine vasopressin/vasotocin, oxytocin and FMRFamide were widely distributed in the spinal cord. Arginine vasopressin/vasotocin-immunoreactive fibers often made contacts with Rohde cell axons.

    The present study indicates that there are at least six separate neuronal systems that contain different peptides, respectively, in the central nervous system of the amphioxus. Their functions remain to be determined. ...
...urotensin I
...arginine vasopressin/vasotocin  
...Angiotensin II  

[Distribution of neuropeptide Y-like and beta-endorphin-like immunoreactivity in the nervous system and Hatschek's pit of amphioxus, Branchiostoma belcheri].  
Using immunohischemical method, we have localized for the first time in the amphioxus, Branchiostoma belcheri, neuropeptide Y (NPY)-like and beta-endorphin (beta-Ep)-like immunoreactivity in nervous system and Hatschek's pit.  
    NPY-immunoreactive (-ir) perikarya appeared in the front and middle areas of the telencephalon and midbrain, as well as in the hindbrain. Dense plexuses of NPY-ir fibers coursed with NPY-ir neurons and formed fine networks. NPY-ir perikarya and fibers were observed in the dorsal and middle areas of spinal cord.  
    Beta-Ep-like immunoreactive perikarya and fibers were located in the front and middle areas of the midbrain, as well as in the spinal cord, but not in the telencephalon and hindbrain. The regions showing beta-Ep immunoreactivity were less than that of NPY.  
    NPY-like and beta-Ep-like immunoreactivity were also found in the Hatschek's pit of amphioxus. These results suggest that NPY and beta-Ep, as an neurotransmitter as in fish, may be involved in the regulation of Hatschek's pit gonadotrophic cells secretory activity in amphioxus, and provide a new morphological evidence for the close relationship between brain and Hatschek's pit in amphioxus."