Number of synaptic vesicles in rat cortical synapses one hour after termination of a seizure during kindling.
Repeated electrical stimulation of the sensorimotor area in the rat cerebral cortex at 10-min intervals led to the formation and progressive lengthening of self-sustained after-discharges [SSAD]. One hour after the third SSAD ended, we evaluated the number of synaptic vesicles in type I synapses according to Gray in the second cortical layer of the homotopical part of the unstimulated hemisphere in the vicinity of the active synaptic zone and the total number of vesicles in sections of the presynaptic bag. We also made a semiquantitative evaluation of exocytotic and endocytotic activity on the presynaptic membrane. No statistically significant differences between the experimental and the control animals were demonstrated in any of the ultrastructural parameters studied. Persistent hyperexcitability of the tissues one hour after the SSAD ended was evidently due to other synaptic transmission mechanisms, which cannot be detected by morphological methods.
Langmeier
M
M
Mares
J
J
D000818:Animals; D002540:Cerebral Cortex / Q000503:physiopathology / Q000648:ultrastructure*; D004562:Electrocardiography; D007696:Kindling, Neurologic; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012640:Seizures / Q000473:pathology* / Q000503:physiopathology; D013569:Synapses / Q000648:ultrastructure*; D013572:Synaptic Vesicles / Q000648:ultrastructure*; D013997:Time Factors