Stroke, Vol 17, 76-82, Copyright © 1986 by American Heart Association
G Rosner, R Graf, K Kataoka and WD Heiss
Simultaneous recordings of several cortical neurons were obtained before,
during and after transient 15 min occlusion of the middle cerebral artery
in cats. With the use of a multiple electrode array consisting of 4-7
platinum/iridium microelectrodes, the cortical pericellular blood flow was
concurrently measured by means of the hydrogen clearance technique.
Hydrogen clearance measurements revealed a homogeneous blood flow
distribution throughout all phases of the experiment in the area covered by
the different microelectrodes. Considering only the results of experiments
with low residual blood flow during ischemia (less than 0.1 ml/g/min),
single unit activity ceased immediately after occlusion and remained so
during the ischemic period. The recovery time of action potentials after
reperfusion ranged from 10 min to 3 hours depending on the examined neuron.
Lower values for discharge rates of the individual cells were generally
observed after reoccurrence, although some units exhibited temporarily an
even higher spike frequency. Furthermore, the spike form usually changed in
that the hyperpolarizing afterpotentials were enlarged after recirculation.
However, some cells with a nearly unchanged spike form were found as well.
The results indicate that the recovery of cell function largely depends on
the individual neuron which supports the idea of a selective functional
vulnerability of cortical neurons in response to ischemia.
ARTICLES
Selective functional vulnerability of cortical neurons following transient MCA-occlusion in the cat