Influence of anterodorsal thalamic nuclei on adrenal function in rats.

Experiments were carried out in order to elucidate a possible role of anterodorsal thalamic nuclei (ADTN) upon adrenal gland function in rats. Bilateral stimulation of ADTN produced a significant decrease in corticosterone concentration (C) in both plasma and adrenal tissue. After exposure to ether vapour, rats with bilateral lesion of ADTN showed that the increase in plasma C was markedly higher than that in the sham lesioned ones. Sham-lesioned stressed rats showed values of adrenal C higher than the values in sham unstressed rats. Whereas, ADTN-lesioned rats showed that adrenal C values were significantly lower than in the lesioned unstressed rats. The concentration of adrenal catecholamines, norepinephrine (NE) and epinephrine (E), in sham-lesioned rats was unaffected by ether stress. In stressed lesioned rats, adrenal glands contained 4 times as much NE and 2 times as much E as did the adrenal glands from lesioned unstressed rats. Our results suggest that the ADTN exert and inhibitory effect on adrenocortical function. They would involved in mediating the effect of stress in adrenal cortex and medulla in rats.