Serotonergic retinopetal axons in the monkey retina.
OBJECTIVE
To describe serotonergic retinopetal axons in monkeys.


METHODS
Whole macaque and baboon retinas, fixed in 4% paraformaldehyde, were labeled with antisera raised against serotonin (5-HT).


RESULTS
Several large-diameter 5-HT-immunoreactive (IR) axons emerged from the optic disk. Most axons ran to the peripheral retina, where they branched extensively. Most terminated in the ganglion cell layer, but a few 5-HT-IR axons terminated in distal inner plexiform or within inner nuclear layer. Some axons branched extensively near the fovea, and a dense plexus of 5-HT-IR axons was also found around the optic disk. Varicose 5-HT-IR axons were also associated with blood vessels, especially in the central retina.


CONCLUSIONS
Immunoreactive serotonin is present in a distinct population of retinopetal axons in the monkey retina. Receptors for serotonin are present in the primate retinas, and based on physiological studies in other mammals, these retinopetal axons are expected to modulate neuronal activity and regulate blood flow.
Gastinger
Matthew J
MJ
Department of Neurobiology and Anatomy, University of Texas Medical School at Houston, Houston, Texas 77225, USA.
Bordt
Andrea S
AS
Bernal
Maria P
MP
Marshak
David W
DW
D000818:Animals; D001369:Axons / Q000378:metabolism*; D005260:Female; D008253:Macaca mulatta; D009412:Nerve Fibers / Q000378:metabolism; D009898:Optic Disk / Q000378:metabolism*; D048530:Papio anubis; D011985:Receptors, Serotonin / Q000378:metabolism; D012160:Retina / Q000378:metabolism*; D012165:Retinal Ganglion Cells / Q000378:metabolism*; D012171:Retinal Vessels / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism*; D014795:Visual Pathways / Q000378:metabolism*
D011985:Receptors, Serotonin; D012701:Serotonin