Conditioning of Rats to Tumbling Trauma by Electroconvulsive Shock

¹ From the Department of Biochemistry, Walter Reed Army Institute of Research, Walter Reed Army Medical Center, Washington, D.C.

Rats were made relatively resistant to the lethal effects of tumbling trauma by a previous series of electroconvulsive shocks (ECS). ECS causes an immediate marked rise in the plasma concentrations of adrenaline and noradrenaline, as a result of the electrical stimulation of the sympathetic nervous system. The plasma concentrations of adrenaline and noradrenaline, which are elevated in response to trauma, show a more rapid fall after termination of trauma in the ECS-conditioned animals than in controls. There is no significant alteration in the sensitivity of ECS-conditioned rats to toxic doses of adrenaline and noradrenaline. It is thought that ECS-conditioning, and probably also the conventional drum-conditioning, are brought about by a diminished reactivity of the sympathetic nervous system after its repeated stimulation.