[Chemical sensitivity of neurons to immobilization emotional stress in the rat].

Chemical sensitivity of the neurones of the medial thalamus (MT) and ventromedial hypothalamus (VMH) to noradrenaline (NA) was studied microionophoretically in conditions of 30-hour immobilization of rats. Chemical sensitivity of single neurons of MT as well as VMH during immobilization is characterized by a certain instability, showed in changes of their reactions at repeated NA applications. These changes were observed significantly more frequently in MT neurones especially at the initial stage of immobilization. At the final stage as well as in unrestrained control animals, changes of the sensitivity were seen significantly more seldom. At the initial stage of rats' immobilization a significant increase of the number of MT and VMH cells responding to NA application by the excitative type of reactions was also observed.