Effect of drum stress on maximal electroconvulsive seizure latency in mice

When mice were exposed to a revolving drum stress (42 rev/min) for a few minutes, a biphasic effect on the latency to tonic extension following a supramaximal electroshock seizure was observed. A two-fold increase in the time to seizure was seen immediately after stress which was followed by a return to control values within 10–15 min. Beginning 15 min later, a second increase in latency occurred which persisted for several hours. No change on the biphasic response pattern was observed if mice were given chlorpromazine or dibenamine prior to stress, or were bilaterally adrenalectomized 4 days prior to study. Reserpine, given in a dose which reduced the latency to tonic extension in non-stressed mice, was found to antagonize both phases of the increased latency seen after drum stress. Catecholamine or corticosteroid release could not be implicated to explain these findings.