Localization of preganglionic neurons that innervate choroidal neurons of pterygopalatine ganglion.
OBJECTIVE
The pterygopalatine ganglion (PPG) receives preganglionic input from the superior salivatory nucleus (SSN) of the facial motor complex and is the main source of parasympathetic input to the choroid in mammals. The present study was undertaken to determine in rats the location and neurotransmitters of SSN neurons innervating those PPG neurons that target the choroid and to determine the location and neurotransmitters of the PPG choroidal neurons themselves.


METHODS
Retrograde labeling from rat choroid using a fluorescent tracer, in combination with immunofluorescence labeling for nitric oxide synthase (NOS), vasoactive intestinal polypeptide (VIP), and choline acetyltransferase (ChAT), was used to characterize the location and neurotransmitters of choroidal PPG neurons. To identify SSN neurons that innervate the choroidal PPG neurons, the Bartha strain of the retrograde transneuronal tracer pseudorabies virus (PRV-Ba) was injected into rat choroid, and immunolabeling for NOS or ChAT was used to characterize their neurochemistry.


RESULTS
Fluorescent retrograde labeling showed that PPG neurons projecting to the choroid contained NOS, VIP, and ChAT and were widely distributed in PPG and its preganglionic root, the greater petrosal nerve. SSN neurons were ChAT(+), and a subset of them was found to contain NOS. PRV-Ba transneuronal retrograde labeling revealed that choroidal preganglionic neurons were localized to the rostral medioventral part of the ipsilateral SSN. The choroidal SSN neurons were ChAT(+) and appeared largely to correspond to the NOS(+) neurons of the SSN.


CONCLUSIONS
These results show that preganglionic neurons in rats that are presumed to regulate choroidal blood flow through the PPG reside within the rostral medioventral SSN, and that NOS is a marker for these SSN neurons.
Cuthbertson
Sherry
S
Department of Anatomy and Neurobiology, University of Tennessee, Memphis, Tennessee, USA.
LeDoux
Mark S
MS
Jones
Seth
S
Jones
Julia
J
Zhou
Qihong
Q
Gong
Suzhen
S
Ryan
Patrick
P
Reiner
Anton
A
D000818:Animals; D001339:Autonomic Fibers, Preganglionic / Q000378:metabolism*; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D002829:Choroid / Q000098:blood supply / Q000294:innervation*; D019084:Fluorescent Antibody Technique, Indirect; D005726:Ganglia, Parasympathetic / Q000033:anatomy & histology* / Q000378:metabolism; D007124:Immunoenzyme Techniques; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I; D010159:Palate / Q000294:innervation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013100:Sphenoid Bone / Q000294:innervation; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism
D014660:Vasoactive Intestinal Peptide; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; C496322:Nos1 protein, rat; D002795:Choline O-Acetyltransferase