Supported in part by U.S.P.H.S. research grants NB-05429-03 and NB-08154-01 from the National Institute of Neurological Diseases and Stroke.
Article first published online: 27 JAN 2005
Copyright © 1970 Wiley-Liss, Inc.
The Anatomical Record
Volume 166, Issue 2, pages 131–141, February 1970
How to Cite
Williams, V. and Grossman, R. G. (1970), Ultrastructure of cortical synapses after failure of presynaptic activity in ischemia,. Anat. Rec., 166: 131–141. doi: 10.1002/ar.1091660202
Presented at the American Association of Anatomists, 81st Annual Meeting, April 9–12, 1968, New Orleans.
- Issue published online: 27 JAN 2005
- Article first published online: 27 JAN 2005
- Manuscript Accepted: 27 AUG 1969
- Manuscript Received: 25 JUL 1968
The fine structure of cerebral cortical synapses was investigated during failure of synaptic transmission produced by ischemia. Presynaptic and postsynaptic potentials evoked in the anterior sigmoid gyrus of the cat by stimulation of the nucleus ventralis lateralis and the DC potential between cortical layer IV and the white matter were recorded with micropipettes during cerebral ischemia produced by arterial hemorrhage in paralyzed, artificially ventilated animals. After failure of the spontaneous electrocorticogram and postsynaptic responses, the presynaptic volley failed with development of depolarization of intracortical fiber terminals and loss of axon terminal excitability. The gyrus was then biopsied and fixed in collidine-buffered OsO4. An altered pattern of distribution of synaptic vesicles was observed after presynaptic afferent fiber terminal activity was abolished by 3.5 to 4.0 minutes of cerebral ischemia. Clumping of vesicles in a region away from the cynaptic cleft was seen in about 10% of synaptic endings, and there was more than a two-fold increase in the number of presynaptic profiles devoid of vesicles in ischemic cortex.