[Effect of thyroliberin on neurons of the sensorimotor cortex].

The effect of thyroliberin (thyrotropin-releasing hormone) on extracellularly recorded spontaneous activity of sensorimotor cortical neurons was studied in experiments on non-anesthetized rabbits. Thyroliberin injected intravenously in doses of 0.1-7.0 mg/kg had an excitatory effect on the cortical neurons. In contrast, thyroliberin had a depressant effect when applied microiontophoretically to individual neurons. It is concluded that the excitatory effect of thyroliberin on the cortex after systemic application is related to the facilitation of subcortical-cortical activating influences. Extracortical receptors of the excitatory type are likely to be responsible for the main central-stimulating properties of thyroliberin.