Projections of neurons in the intestinal nerve of Remak to the chicken intestine.
To date, the exact site of the extrinsic postganglionic neurons innervating the intramural plexuses in the chicken intestine is unknown. In this study, neurons in the intestinal nerve of Remak (INR) were immunohistochemically labelled by injecting cholera toxin subunit B (CTb) into each one of the jejunal, ileal, cecal and rectal walls. The CTb-immunoreactive (IR) neurons were counted, and some sections from the rectal portion of INR (rectal INR) were also immunostained for either tyrosine hydroxylase (TH) or methionine enkephalin (mENK). Following injection of CTb into the jejunum or ileum, only a few CTb-IR neurons were found in the jejunal or ileal part of INR caudal to the injection site. Following injection into the more caudal intestine, CTb-IR neurons were seen in the rectal INR. Of the 3490 CTb-IR neurons that were counted in the rectal INR, 40% projected into the rostral rectum, 24% into the caudal rectum, 17% into the ileum, 10% into the cecum and only 9% into the middle rectum. Rostrocaudally dividing the rectal INR into three parts, one third of the CTb-IR neurons in the rostral part projected into the rostral rectum, the majority of CTb-IR ones in the middle part innervated the rostral rectum, and half of CTb-IR neurons in the caudal part ran into the caudal rectum. Consequently, the rostral rectum received the densest innervation, and almost all the neurons in the rectal INR exhibited an ascending projection. By double labelling, CTb-IR neurons containing TH or mENK were observed in the rectal INR after the rectal injection. The mENK-IR neurons localized in middle and caudal parts of rectal INR amounted to one third of the total CTb-IR neurons, and mainly projected into the rostral and caudal rectum. TH-and mENK-immunonegative neurons were restricted to the rostral part of rectal INR and the more rostral level.
Department of Veterinary Anatomy, School of Agriculture, Nagoya University, Japan.
M
M
Suzuki
Y
Y
Ohmori
T
T
Watanabe
D000818:Animals; D017776:Autonomic Pathways / Q000166:cytology / Q000502:physiology; D002452:Cell Count; D002645:Chickens / Q000502:physiology*; D002772:Cholera Toxin; D004744:Enkephalin, Methionine / Q000378:metabolism; D007150:Immunohistochemistry; D007422:Intestines / Q000294:innervation*; D008297:Male; D009474:Neurons / Q000502:physiology*; D017779:Sympathetic Fibers, Postganglionic / Q000166:cytology / Q000502:physiology; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
D004744:Enkephalin, Methionine; D002772:Cholera Toxin; D014446:Tyrosine 3-Monooxygenase