The role of endogenous catecholamines in the regulation of electrocortical activity in the encephale isole cat.

Experiments were performed on encephale isole cats. The cats were either untreated or pretreated with reserpine, alpha-methyl-p-tyrosine (AMPT) or FLA 63, and the depletion of endogenous noradrenaline was determined by fluorescence microscopy. Pretreatment with reserpine reduced waking and spindle sleep while the synthesis inhibitors did not. A combined pretreatment with reserpine and AMPT or FLA 63 was necessary to deplete totally brain stem noradrenaline. Under these circumstances, behavioural arousal was abolished and all electrocortical activity except spindling was also abolished. Injection of L-DOPA into cats pretreated with reserpine and AMPT produced behavioural alerting and low voltage, high frequency electrocortical activity. In cats pretreated with reserpine and FLA 63, the minimum effective dose of L-DOPA was often elevated, and when the low voltage, high frequency activity occurred, it was accompanied by spindling. It was accompanied by spindling. It is suggested that dopamine and noradrenaline independently modulate electrocortical activity, dopamine mediating spindling, and noradrenaline inhibiting spindling but mediating low voltage, high frequency activity.