Preganglionic neurons of the sphenopalatine ganglia reside in the dorsal facial area of the medulla in cats.
Stimulation of the sphenopalatine ganglion (SPG), a parasympathetic ganglion of the facial nerve, or the dorsal facial area (DFA), an area in the lateral tegmental field just dorsal to the facial nucleus, induces an increase in blood flow of the common carotid artery (CCA). This study attempted to clarify the anatomical and functional relationships between the SPG and the DFA, and to demonstrate putative serotonergic (5-HT) and substance P (SP) innervations to the neurons of the DFA in regulation of the CCA blood flow in cats. Horseradish peroxidase (HRP), a retrograde tracer, was injected in the SPG. All HRP-labeled neurons were distributed in the reticular areas dorsal and lateral to the superior olivary nucleus and the facial nucleus, extending from the caudal half of the superior olivary nucleus to the rostral 3/4 of the facial nucleus on the HRP-injected side. They were grouped into five clusters, namely lateral circumference of the superior olivary nucleus, dorsal circumference of the superior olivary nucleus, lateral circumference of the facial nucleus, dorsal circumference of the facial nucleus, and the DFA. The percentage of HRP-neurons in each cluster was 0.5 +/- 0.1% (mean +/- S.E., n=6), 15.2 +/- 1.9%, 23.7 +/- 0.9%, 52.5 +/- 1.7%, and 8.3 +/- 0.7%, respectively. Glutamate stimulation of the DFA (at 5.0 to 7.0 mm rostral to the obex, 2.8 to 4.0 mm lateral to the midline, and 2.5 to 3.5 mm ventral to the dorsal surface of the medulla), but not other areas, resulted in the increased CCA blood flow. The 5HT- and SP-immunoreactive nerve terminals abutted on the ChAT-immunoreactive cell body (preganglionic neurons) in the DFA. In conclusion, parasympathetic preganglionic neurons in the DFA project fibers to the SPG, are innervated by 5HT- and SP-like nerve terminals, and are responsible for regulation of the CCA blood flow. They may be also important in regulation of the cerebral blood flow.
Chyi
Theresa
T
Department of Biology, Tunghai University, Taichung.
Wang
Shwun-De
SD
Gong
Chi-Li
CL
Lin
Sin-Zon
SZ
Cheng
Vie
V
Kuo
Jon-Son
JS
D000818:Animals; D017536:Carotid Artery, Common / Q000502:physiology*; D002415:Cats; D002795:Choline O-Acetyltransferase / Q000032:analysis; D004558:Electric Stimulation; D005154:Facial Nerve / Q000502:physiology*; D005260:Female; D005726:Ganglia, Parasympathetic / Q000502:physiology*; D018698:Glutamic Acid / Q000494:pharmacology; D007150:Immunohistochemistry; D008297:Male; D008526:Medulla Oblongata / Q000502:physiology*; D012039:Regional Blood Flow; D012701:Serotonin / Q000032:analysis; D013373:Substance P / Q000032:analysis
D012701:Serotonin; D013373:Substance P; D018698:Glutamic Acid; D002795:Choline O-Acetyltransferase