A light and electron microscopic study of the preoptic nucleus of the grass frog (Rana pipiens), under normal conditions and following transection of the preoptico-neurohypophysial tract.
Degenerative and regenerative processes occur in the preoptic neurons following transection of the preoptico-neurohypophysial tract. Three types of responses after transection were observed: affected, recovered, and degenerated neurons. However, transection of the tract did not stop the synthesis of neurosecretory granulated vesicles. The affected neurosecretory neurons showed nuclear changes, increased number of Golgi complexes, and dilated cisternae of rER, as well as, an increased number of dense bodies. The recovered neurosecretory neurons contained long non-dilated cisternae of rER which were organized in a concentric manner. Also seen were large nuclei with evenly distributed chromatin, less active Golgi complexes, and vesicles. The degenerated neurosecretory neurons exhibit pyknotic nuclei, a net of dilated cisternae of rER, dense bodies, and electron dense cytoplasm.
al-Tikriti
M A
MA
Department of Animal Science, College of Veterinary Medicine, University of Tennessee, Knoxville 37901-1071.
Henry
R W
RW
D000818:Animals; D008854:Microscopy, Electron; D009410:Nerve Degeneration; D010904:Pituitary Gland, Posterior / Q000502:physiology; D011301:Preoptic Area / Q000502:physiology / Q000648:ultrastructure*; D011894:Rana pipiens / Q000033:anatomy & histology*