Abstract
Electron micrographs, stained Epon-embedded sections, and silver stains of the ciliary ganglion of chickens 19 days prehatched, 4 days, 5 weeks, 6 months, and 1 to 2 years of age were studied. The majority of ganglion cells are large neurons; smaller cells are restricted to a dorsal, distal part of the ganglion. The following description applies to the large neurons. Three to twenty lamellae of loose, semicompact, and compact myelin ensheathe virtually every neuron. All these types of myelin form the sheath of a single neuron. The lamellae greatly increase in number and in compactness during the period between the 19-day embryo and the 4-day-old chick. During the period between the 4-day chick and the adult chicken, the myelin becomes only slightly thicker and denser. The calyx is a large synaptic terminal encircling virtually every neuron in the ganglion up to 5 weeks of age. At 6 months of age, the calyx appears to break up; only about half the number of neurons in the ganglion have this large terminal, while the remaining neurons have numerous relatively small, boutonlike synapses. This rather remarkable transformation in the structure of the calyx is virtually complete in the 1- to 2-year-old chickens. In these older chickens all the cells have boutons, and calyces are no longer present. The entering preterminal fiber, the calyx, the neuron, and the axon hillock can all have myelin lamellae on them. It is possible that this entire complex is effectively insulated by the myelin sheath. No synaptic discs or fusion of the membranes of the preterminal fiber and the postganglionic neuron are seen. The chick ciliary ganglion cells are the only myelinated neurons so far described which receive synapses. The neurons in the small-cell part of the ganglion do not have calyces and are not ensheathed by myelin lamellae at any age.
Full Text
The Full Text of this article is available as a PDF (2.2 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- COUTEAUX R. THE DIFFERENTIATION OF SYNAPTIC AREAS. Proc R Soc Lond B Biol Sci. 1963 Nov 19;158:457–480. doi: 10.1098/rspb.1963.0058. [DOI] [PubMed] [Google Scholar]
- DE LORENZO A. J. The fine structure of synapses in the ciliary ganglion of the chick. J Biophys Biochem Cytol. 1960 Feb;7:31–36. doi: 10.1083/jcb.7.1.31. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Huxley A. F., Stämpfli R. Evidence for saltatory conduction in peripheral myelinated nerve fibres. J Physiol. 1949 May 15;108(3):315–339. [PMC free article] [PubMed] [Google Scholar]
- KARNOVSKY M. J. Simple methods for "staining with lead" at high pH in electron microscopy. J Biophys Biochem Cytol. 1961 Dec;11:729–732. doi: 10.1083/jcb.11.3.729. [DOI] [PMC free article] [PubMed] [Google Scholar]
- LUFT J. H. Improvements in epoxy resin embedding methods. J Biophys Biochem Cytol. 1961 Feb;9:409–414. doi: 10.1083/jcb.9.2.409. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MARTIN A. R., PILAR G. DUAL MODE OF SYNAPTIC TRANSMISSION IN THE AVIAN CILIARY GANGLION. J Physiol. 1963 Sep;168:443–463. doi: 10.1113/jphysiol.1963.sp007202. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MARTIN A. R., PILAR G. TRANSMISSION THROUGH THE CILIARY GANGLION OF THE CHICK. J Physiol. 1963 Sep;168:464–475. doi: 10.1113/jphysiol.1963.sp007203. [DOI] [PMC free article] [PubMed] [Google Scholar]
- RICHARDSON K. C., JARETT L., FINKE E. H. Embedding in epoxy resins for ultrathin sectioning in electron microscopy. Stain Technol. 1960 Nov;35:313–323. doi: 10.3109/10520296009114754. [DOI] [PubMed] [Google Scholar]
- ROBERTSON J. D., BODENHEIMER T. S., STAGE D. E. THE ULTRASTRUCTURE OF MAUTHNER CELL SYNAPSES AND NODES IN GOLDFISH BRAINS. J Cell Biol. 1963 Oct;19:159–199. doi: 10.1083/jcb.19.1.159. [DOI] [PMC free article] [PubMed] [Google Scholar]
- ROSENBLUTH J., PALAY S. L. The fine structure of nerve cell bodies and their myelin sheaths in the eighth nerve ganglion of the goldfish. J Biophys Biochem Cytol. 1961 Apr;9:853–877. doi: 10.1083/jcb.9.4.853. [DOI] [PMC free article] [PubMed] [Google Scholar]
- ROSENBLUTH J. The fine structure of acoustic ganglia in the rat. J Cell Biol. 1962 Feb;12:329–359. doi: 10.1083/jcb.12.2.329. [DOI] [PMC free article] [PubMed] [Google Scholar]
- TERZUOLO C. Ricerche sul ganglio ciliare degli uccelli; connessioni, mutamenti in-relazione all'eta e dopo recisione delle fibre pregangliari. Z Zellforsch Mikrosk Anat. 1951;36(3):255–267. [PubMed] [Google Scholar]