[The effect of the experimentally induced failure of catecholaminergic transmission on the neuronal activity of the thalamic ventrolateral nucleus].

In chronic experiments on cats the background activity of 272 neurons of the ventrolateral thalamic nucleus was registered extracellularly before and after the systemic injection of haloperidol and droperidol (neuroleptics) in cataleptic doses. Autocorrelation and spectral analyses have revealed rhythmic changes in the frequency of the background neuronal activity with periodicity measured by parts of seconds (0.2-0.8 s), seconds (1.5-10 s) and second tens (12-30 s). Just as the number of neurons with individual forms of the rhythmic activity did not exceed 6-8% in intact animals, after administration of neuroleptics it increased to 18-30%. A rise of the neurons' number with two rhythmic processes in the same impulsive flow was observed. Experimental results were compared with clinical data. In patients with parkinsonism the number of neurons with different variants of fluctuations in the rhythmic frequency of the spike activity reached 19-46%, in patients with torsion-muscle dystonia it did not exceed 4-8%. It is supposed that the genesis of augmented rhythmic impulsation of the thalamic neurons in patients with parkinsonism is connected with a break of the catecholaminergic transmission both of the dopaminergic and alpha-adrenergic one.