Pituitary adenylate cyclase-activating peptide-immunoreactive nerve fibers in the cat eye.
OBJECTIVE
To study the occurrence and distribution of the neuropeptide pituitary adenylate cyclase-activating peptide (PACAP) in ocular and orbital structures of the cat.


METHODS
Immunocyto-chemistry to localize PACAP and double immunostaining to detect co-localization of PACAP with other neuropeptides.


RESULTS
Numerous PACAP-immunoreactive nerve fibers were observed in the lacrimal gland, choroid and retroocular arteries. There was a sparse supply of PACAP-containing nerve fibers in the iris, ciliary body and conjunctiva. Subpopulations of PACAP-containing nerve fibers stored vasoactive intestinal peptide (VIP) or calcitonin gene-related peptide (CGRP). Around 10% of the ganglion cells in the sphenopalatine ganglion harbored PACAP immunoreactivity. In the trigeminal ganglion around 5% of the neuronal cell bodies and in the ciliary ganglion only occasional ganglion cells contained PACAP immunoreactivity. PACAP immunoreactivity co-localized with VIP in the sphenopalatine ganglion and with CGRP in the trigeminal ganglion.


CONCLUSIONS
PACAP-containing nerves in the eye and associated structures demonstrate a distribution pattern resembling that of VIP. Subpopulations of nerve fibers containing PACAP immunoreactivity store VIP or CGRP immunoreactivity. Neuronal PACAP in the eye and orbit may take part in regulation of smooth muscle tone, glandular secretion and sensory processing.
Elsås
T
T
Department of Ophthalmology, University Hospital of Trondheim, Norway.
Uddman
R
R
Sundler
F
F
D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000032:analysis; D002415:Cats; D005123:Eye / Q000737:chemistry / Q000294:innervation*; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D017950:Ganglia, Sensory / Q000737:chemistry*; D008297:Male; D009412:Nerve Fibers / Q000737:chemistry*; D009479:Neuropeptides / Q000032:analysis*; D018377:Neurotransmitter Agents / Q000032:analysis*; D009915:Orbit / Q000294:innervation*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D014660:Vasoactive Intestinal Peptide / Q000032:analysis
D009479:Neuropeptides; D018377:Neurotransmitter Agents; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D014660:Vasoactive Intestinal Peptide; D015740:Calcitonin Gene-Related Peptide