Species differences in choroidal vasodilative innervation: evidence for specific intrinsic nitrergic and VIP-positive neurons in the human eye.
OBJECTIVE
There is evidence that vasodilation of choroidal vessels results from facial nerve stimulation. To obtain more information about the role of this innervation, the authors examined the presence and spatial organization of nitrergic and vasoactive intestinal peptide (VIP) immunoreactive nerves in the human choroid. For comparison, the choroid of rabbit and rat eyes, with different types of retinal vascularization and no fovea, were studied.


METHODS
Whole mounts of five human, nine rat, and two rabbit choroids were stained for NADPH-diaphorase. In addition, immunocytochemical staining was carried out on tangential frozen sections of two human choroids using antibodies against nitric oxide synthase (NOS), synaptophysin, and VIP.


RESULTS
In all species, a perivascular network of diaphorase-positive nerve fibers with varicose terminals accompanied the arteries and arterioles of the choroidal stroma. A striking difference to rat and rabbit choroids was the presence of numerous positively stained ganglion cells in human choroids. Positively stained axons connected the neurons with each other and with the perivascular network. Most of the ganglion cells were concentrated in the temporal-central region, adjacent to the fovea. Immunocytochemically, the choroidal ganglion cells were immunoreactive for NOS. Some ganglion cells stained for VIP. Staining for synaptophysin demonstrated varicose terminals innervating the perikarya of the ganglion cells. Many of these terminals stained for NOS and VIP.


CONCLUSIONS
The presence of an intrinsic nerve cell plexus that is specifically localized in human eyes in the temporal-central portion of the choroid indicates a functional significance of the nitrergic choroidal innervation for the fovea.
Flügel
C
C
Department of Anatomy II, University of Erlangen-Nürnberg, Germany.
Tamm
E R
ER
Mayer
B
B
Lütjen-Drecoll
E
E
D000368:Aged; D000369:Aged, 80 and over; D000594:Amino Acid Oxidoreductases / Q000378:metabolism*; D000818:Animals; D002829:Choroid / Q000098:blood supply / Q000294:innervation*; D005455:Fluorescent Antibody Technique; D017950:Ganglia, Sensory / Q000378:metabolism; D006801:Humans; D008875:Middle Aged; D009252:NADPH Dehydrogenase / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D019001:Nitric Oxide Synthase; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D013045:Species Specificity; D016708:Synaptophysin / Q000378:metabolism; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism*; D014664:Vasodilation
D016708:Synaptophysin; D014660:Vasoactive Intestinal Peptide; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases; D009252:NADPH Dehydrogenase