Differential distribution of nerve terminals immunoreactive for substance P and cholecystokinin in the sympathetic preganglionic cell column of the filefish Stephanolepis cirrhifer.
Immunoreactivity for substance P and cholecystokinin-8 was examined in the nerve fibers in the central autonomic nucleus, a cell column for sympathetic preganglionic neurons, in the filefish Stephanolepis cirrhifer. Substance P-immunoreactive fibers were distributed throughout the entire rostrocaudal extent, but were more abundant in the caudal part of the column, where substance P-immunoreactive varicosities sometimes made contacts with the sympathetic preganglionic neurons. Cholecystokinin-8-immunoreactive fibers were found almost entirely in the rostral part of the column, where a dense network of varicosities was in close apposition to a considerable number of the sympathetic preganglionic neurons. Double labeling immunohistochemistry showed that substance P fibers and cholecystokin-8 fibers were entirely different, and distinct from serotonin-immunoreactive fibers. By using immunoelectron microscopy, synaptic specialization was sometimes observed between the dendrites of preganglionic neurons and varicosities immunoreactive for substance P and cholecystokinin-8. Substance P- and cholecystokinin-8 fibers were seen from the descending trigeminal tract, through the dorsolateral funiculus and the ventral portion of the dorsal horn, to the central autonomic nucleus. After colchicine treatment, substance P-immunoreactive perikarya were found in the cranial and spinal sensory ganglia. These results suggest that the sympathetic preganglionic neurons of the filefish receive innervation by substance P fibers and cholecystokinin fibers, and that the former might be of primary sensory origin. Topographical distribution of cholecystokinin-8-immunoreactive terminals in the central autonomic nucleus along the rostrocaudal extent might underlie the differential regulation of sympathetic activity via a distinct population of sympathetic preganglionic neurons.
Funakoshi
K
K
Department of Anatomy, Yokohama City University School of Medicine, Yokohama 236-0004, Japan. funako@med.yokohama-cu.ac.jp
Kadota
T
T
Atobe
Y
Y
Nakano
M
M
Goris
R C
RC
Kishida
R
R
D000818:Animals; D001339:Autonomic Fibers, Preganglionic / Q000166:cytology / Q000378:metabolism*; D002766:Cholecystokinin / Q000378:metabolism*; D005399:Fishes / Q000033:anatomy & histology / Q000378:metabolism*; D017950:Ganglia, Sensory / Q000166:cytology / Q000378:metabolism; D008526:Medulla Oblongata / Q000166:cytology / Q000378:metabolism; D009434:Neural Pathways / Q000166:cytology / Q000378:metabolism; D017729:Presynaptic Terminals / Q000378:metabolism* / Q000648:ultrastructure; D012844:Sincalide / Q000378:metabolism; D013116:Spinal Cord / Q000166:cytology / Q000378:metabolism*; D013373:Substance P / Q000378:metabolism*; D013564:Sympathetic Nervous System / Q000166:cytology / Q000378:metabolism*
D013373:Substance P; D002766:Cholecystokinin; D012844:Sincalide