Effects of thyroliberin on membrane potential and the pattern of spontaneous activity of neurons in the respiratory center in in vitro studies in rats.

Patch-clamp experiments on transverse brainstem slices from rats were performed to study the effects of thyroliberin (10(-8) M) on the membrane potential and spontaneous activity of neurons in two areas of the respiratory center: the ventrolateral area of the solitary tract nucleus and the pre-Botzinger complex. Thyroliberin induced membrane depolarization of neurons in the respiratory center and increased their spike activity. The pattern of activity of neurons in the pre-Botzinger complex showed decreases in the time intervals between the beginnings of bursts in response to thyroliberin. In some cases, thyroliberin led to the appearance of spike activity in initially "silent" neurons; "silent" neurons in the solitary tract nucleus became tonically active, while those in the pre-Botzinger complex showed burst activity. These results provide evidence for the existence of an indirect regulatory influence for thyroliberin on respiratory center neurons, operating at the membrane level.