Changes in some ultrastructural parameters of cortical synapses in the initial phases of kindling
Langmeier, M.; Mares, J.
Physiologia Bohemoslovaca 33(4): 367-375
1984
ISSN/ISBN: 0369-9463 PMID: 6484027 Document Number: 233967
Repeated electrical stimulation of the sensorimotor region of rat cerebral cortex at 10 min intervals led to the development and progressive prolongation of self-sustained after-discharges (SSAD). One minute after the 3rd SSAD ended, an electronoptic morphological analysis of type I synapses after Gray from the 2nd cortical layer of the homotopic area of the unstimulated hemisphere was carried out. In the experimental animals, an 11.7% increase in the area of the presynaptic bag and a 5.5% increase in its perimeter were demonstrated. The number of agranular synaptic vesicles per constant unit area fell by 70.8%. The area of the mitochondria in the presynaptic ending increased by 49.8% and their perimeter by 16.1%. The area of the postsynaptic element increased by 34.1% and its perimeter by 15.7%. Changes in the synapses are evaluated as manifestations of exhaustion and primarily as a manifestation of ion shifts during the epileptic seizure. Incipent activation of restitution mechanisms in the structures of the synaptic apparatus within a very short time after termination of the seizure is seen.