The effect of repeated electroconvulsive shock treatment and chronic lithium feeding on the release of norepinephrine from rat cortical vesicular preparations

1. The effect of repeated electroconvulsive shock (ECS) treatment and chronic LiC1 feeding on calcium-dependent, K⁺-evoked release of [³H] norepinephrine from rat cortical vesicular preparation was studied. 2. There was no significant effect of either acute or repeated ECS treatment on [³H]norepinephrine release in cortical vesicles obtained from animals treated for either 1 or 10 days. Release of norepinephrine was examined over a range of CaCl₂ concentrations. 3. Clonidine effectively inhibited release of [³H]norepinephrine in cortical vesicles obtained from control and ECS-treated animals. 4. K⁺-evoked release of [³H]norepinephrine at low (0.2 m M) and high (1.0 m M) CaCl₂ concentrations was significantly increased in cortical vesicles obtained from LiCl-treated animals. Clonidine effectively inhibited release of [³H]norepinephrine in cortical vesicles obtained from both control and LiCl-fed animals. 5. These results suggest a possible common mechanism of action of antidepressant drug therapy on presynaptic release of norepinephrine from nerve terminals.