[Function of the hypothalamo-thyroid system after administration of kainate into the ventrolateral portion of the...

Contribution of the bulbar structures to mechanisms of realization of the hypothalamo-thyroid system feedback was studied in experiments on 73 adult male Wistar rats. Histologically confirmed unilateral destruction of neurones in the caudal part of medulla oblongata ventral portions after injection of 0.65 micrograms of kainate as soon as 30 min after injection was paralleled by a trend to increase of the blood serum levels of triiodothyronine and thyroxin-binding globulin, this increase attaining reliable values by day 7 after destruction, when the effects of operation stress levelled. During the same period we observed activation of glucocorticoid-dependent choline-, serotonin-, and noradrenergic-processes in the mediobasal zone of the hypothalamus, this indicating the presence of functional relationships of medulla oblongata ventral portions with the hypothalamo thyroid system realized by disinhibition of this system during destruction of neurones in the caudal part of the ventral portion of medulla oblongata.