A voltammetric technique was used (differential pulse voltammetry with a carbon fibre microelectrode) to investigate dynamics of the changes of catecholamine overflow in the corpus striatum following electroconvulsive stimulation (ECS) of chloral hydrate-anaesthetized rats. Application of "maximal" ECS (50 Hz, AC, sine wave, approximately 150 mA, 0.2 s) caused large enhancement of catechol-oxidative current (CA.OC): In the first minute after its arrest, the CA.OC peak raised to 1032 +/- 405% (n = 5, mean +/- S.D.) of the controls (P < or = 0.001, Student's t-test). This large elevation of the extracellular catecholamine content ceased rapidly--the baseline level was attained in the second minute. CA.OC changes evoked by a "minimal" ECS (50 Hz, AC, sine wave, approximately 30 mA, 0.2 s) were equivocal in the first minute (increase, decrease: 145 +/- 56%, P > 0.05, n = 6). Possible mechanisms of the ECS therapeutic effect are discussed.

Institute of Normal and Pathological Physiology Slovak Academy of Sciences Bratislava