Effects of TRH on ballistic wrist movements in cerebellar cortical atrophy: improvement of two genuine deficiencies but not of the major one.
Thyrotropin-releasing hormone (TRH) has been claimed to improve cerebellar ataxia in patients with idiopathic sporadic cerebellar cortical atrophy (CCA). We analysed the effects of intravenous administration of TRH (1 mg) in ballistic wrist flexions movements in 10 healthy subjects and in eight patients with CCA. The associated agonist and antagonist electromyographic (EMG) activities were recorded. In healthy subjects, TRH did modify neither the movement amplitudes, nor the intensity of the agonist and antagonist EMG activities. Before TRH administration, patients with CCA exhibited a hypermetria which was associated with a delayed onset of the antagonist activity. Moreover, the intensity of EMG activity in both the agonist and the antagonist muscles were reduced. After TRH, the hypermetria and the delayed onset latencies of the antagonist EMG activities were unchanged but the intensity of both the agonist and the antagonist EMG activities increased. TRH could increase the magnitude of agonist and antagonist EMG activities in patients with CCA by exerting an excitatory effect directly on motoneurons or by modulating at the supraspinal level the central commands to agonist and antagonist motoneuron pools. Copyright Rapid Science Ltd
Manto
M
Belgian National Research Foundation, Hopital Erasme, Bruxelles, Belgium.
Godaux
E
Hildebrand
J
Jacquy
J