Substance P-immunoreactive neurons in the rostromedian area of the midbrain send axons to the lower spinal cord in the chicken.
Substance P-immunoreactivity in neurons projecting to the spinal cord was examined using retrograde tract-tracing method combined with immunohistochemical techniques in chickens. Many small substance P-immunoreactive neurons were densely clustered in the midline area in the rostral midbrain, the rostromedian area (80% of the neurons in the rostromedian area). Some of these substance P-immunoreactive neurons in the rostromedian area (about 20% of substance P-immunoreactive neurons) were retrogradely labeled by small injections of wheat germ agglutinin conjugated horseradish peroxidase into the central part of the lumber segments including the intermediomedial nucleus, suggesting the projections from the rostromedian area to the lower spinal preganglionic regions. From the present data and mammalian previous studies, it was suggested that the midline area in the midbrain has fiber connections with the regions related autonomic functions, and all of which exhibit substance P-immunoreactivity.
Naito
J
J
Animal Morphology and Function, Division of Biofunctional Development, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan. naitow@nuagrl.agr.nagoya-u.ac.jp
Shiraishi
N
N
Fujiwara
A
A
Inoue
K
K
D000818:Animals; D000906:Antibodies; D001341:Autonomic Nervous System / Q000737:chemistry / Q000166:cytology; D001369:Axons / Q000737:chemistry; D002645:Chickens; D008297:Male; D008636:Mesencephalon / Q000737:chemistry / Q000166:cytology*; D009434:Neural Pathways; D009474:Neurons / Q000737:chemistry* / Q000648:ultrastructure; D013116:Spinal Cord / Q000737:chemistry / Q000166:cytology*; D013373:Substance P / Q000032:analysis* / Q000276:immunology; D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate
D000906:Antibodies; D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate; D013373:Substance P