title: [Quantitative analysis of the isthmo-optic nucleus and projection neurons to the retina in adult fowl (Gallus gallus domesticus)].
abstract: Quantitative analysis of the isthmo-optic nucleus (IO) and centrifugal projection to the retina in the fowl was made using Nissl preparation and retrograde horseradish peroxidase (HRP) methods. Seven adult fowls (Gallus gallus domesticus) were used for Nissl stain. Serial sections were cut on a freezing microtome at 60 microns and stained with cresyl violet. IO was situated just medial to the caudal part of the tectum and laterodorsal surface of the brain stem. Rostrocaudal extension of IO was about 800-1,000 microns. The average total volume and neuronal population of the IO was 280 x 10(-3) mm3 and 5,600 neurons, respectively. Eight animals were used for HRP study. One hundred microliters of 30% HRP solution in physiological saline was injected into the vitreous body of one eye of each hen. Serial transverse sections of 60 microns were treated with tetramethyl benzidine (TMB). Many labeled neurons were found in contralateral brain stem. Average total number of contralateral HRP-labeled cells in IO and peri-IO were 5,268 and 1,492, respectively. Labeled neurons peri-IO were mainly distributed ventrally and rostrally to IO. No labeled neurons in IO, and only a few labeled neurons peri-IO were found ipsilaterally. The number of HRP-labeled neurons in IO corresponded to the neuronal population of IO in Nissl preparation, which suggested that most of isthmo-optic neurons might be projecting to the contralateral retina. In contrast to the round and small IO neurons (long axis 15-20 microns, short axis 10-20 microns), peri-IO neurons were multipolar and longer (long axis 15-30 microns, short axis 10-25 microns).
authors.affiliation: Department of Bioproductive Science, Faculty of Agriculture, Utsunomiya University, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Sugita
authors.forename: M
authors.initials: M
authors.lastname: Yamada
mesh_terms: D000818:Animals; D002452:Cell Count; D002645:Chickens / Q000033:anatomy & histology*; D005260:Female; D006651:Histocytochemistry; D006735:Horseradish Peroxidase; D009474:Neurons / Q000166:cytology; D009900:Optic Nerve / Q000033:anatomy & histology / Q000166:cytology*; D012160:Retina / Q000033:anatomy & histology / Q000166:cytology*
chemical_list: D006735:Horseradish Peroxidase