RESUMEN
BACKGROUND: Reversible changes in subthalamic nucleus (STN) activity, detected by microelectrode recording (MER), are reported in three patients who received an intravenous betablocker, metoprolol, during deep brain stimulation (DBS) for Parkinson's disease (PD). METHODS: Metoprolol (MP) was given intravenously to reduce blood pressure during surgery. Systolic blood pressure dropped by 4, 11 and 17%, indicating a systemic beta - adrenoceptor blocking effect. FINDINGS: In all patients, the bursting spiking activity of the STN was temporarily suppressed, after the application of MP. Unexpectedly, a transient reduction in Parkinson symptoms (rigidity) was recorded during suppression of STN spiking activity in patient 2. CONCLUSION: The reversible suppression of STN activity and Parkinson symptoms with the beta1-selective adrenoceptor antagonist MP has not been reported. It supports the theory, that--as recently reported in the rat--the human STN is influenced by adrenergic inputs. This report supports the possible application of adrenergic antagonist drugs for the use in Parkinson's disease and advocates additional neurophysiological and pharmacological research in this field.