Abstract
Electron micrographs are presented of synaptic regions encountered in sections of frog sympathetic ganglia and earthworm nerve cord neuropile. Pre- and postsynaptic neuronal elements each appear to have a membrane 70 to 100 A thick, separated from each other over the synaptic area by an intermembranal space 100 to 150 A across. A granular or vesicular component, here designated the synaptic vesicles, is encountered on the presynaptic side of the synapse and consists of numerous oval or spherical bodies 200 to 500 A in diameter, with dense circumferences and lighter centers. Synaptic vesicles are encountered in close relationship to the synaptic membrane. In the earthworm neuropile elongated vesicles are found extending through perforations or gaps in the presynaptic membrane, with portions of vesicles appearing in the intermembranal space. Mitochondria are encountered in the vicinity of the synapse, and in the frog, a submicroscopic filamentary component can be seen in the presynaptic member extending up to the region where the vesicles are found, but terminating short of the synapse itself.
Full Text
The Full Text of this article is available as a PDF (1.1 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- BULLOCK T. H. The invertebrate neuron junction. Cold Spring Harb Symp Quant Biol. 1952;17:267–273. doi: 10.1101/sqb.1952.017.01.024. [DOI] [PubMed] [Google Scholar]
- DE ROBERTIS E. D., BENNETT H. S. A submicroscopic vesicular component of Schwann cells and nerve satellite cells. Exp Cell Res. 1954 May;6(2):543–545. doi: 10.1016/0014-4827(54)90209-8. [DOI] [PubMed] [Google Scholar]
- HILLARP N. A., LAGERSTEDT S., NILSON B. The isolation of a granular fraction from the suprarenal medulla, containing the sympathomimetic catechol amines. Acta Physiol Scand. 1953 Oct 6;29(2-3):251–263. doi: 10.1111/j.1748-1716.1953.tb01022.x. [DOI] [PubMed] [Google Scholar]
- PALADE G. E. The fine structure of mitochondria. Anat Rec. 1952 Nov;114(3):427–451. doi: 10.1002/ar.1091140304. [DOI] [PubMed] [Google Scholar]
- PORTER K. R., BLUM J. A study in microtomy for electron microscopy. Anat Rec. 1953 Dec;117(4):685–710. doi: 10.1002/ar.1091170403. [DOI] [PubMed] [Google Scholar]
- PORTER K. R. Observations on a submicroscopic basophilic component of cytoplasm. J Exp Med. 1953 May;97(5):727–750. doi: 10.1084/jem.97.5.727. [DOI] [PMC free article] [PubMed] [Google Scholar]
- ROBERTSON J. D. Ultrastructure of two invertebrate synapses. Proc Soc Exp Biol Med. 1953 Feb;82(2):219–223. doi: 10.3181/00379727-82-20071. [DOI] [PubMed] [Google Scholar]