TY - JOUR
T1 - Ultrastructure of cortical synapses after failure of presynaptic activity in ischemia,
AU - Williams, Vick
AU - Grossman, Robert G.
PY - 1970/1/1
Y1 - 1970/1/1
N2 - 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.
AB - 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.
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U2 - 10.1002/ar.1091660202
DO - 10.1002/ar.1091660202
M3 - Article
C2 - 4313222
AN - SCOPUS:0014739595
SN - 0003-276X
VL - 166
SP - 131
EP - 141
JO - The Anatomical Record
JF - The Anatomical Record
IS - 2
ER -