Bj. Yates et al., ORGANIZATION OF VESTIBULAR INPUTS TO NUCLEUS-TRACTUS-SOLITARIUS AND ADJACENT STRUCTURES IN CAT BRAIN-STEM, American journal of physiology. Regulatory, integrative and comparative physiology, 36(4), 1994, pp. 180000974-180000983
The vestibular system is involved in maintaining stable blood pressure
and respiration during changes in posture and is essential for elicit
ing motion sickness-related vomiting. Because the nucleus tractus soli
tarius (NTS) participates in the regulation of sympathetic and inspira
tory outflow and the triggering of emesis, we tested the hypothesis th
at this region receives vestibular inputs in cats. In one set of exper
iments, microinjections of the tracer Phaseolus vulgaris leucoagglutin
in into the medial and inferior vestibular nuclei labeled projections
to the middle and lateral regions of the NTS. In electrophysiological
experiments, electrical stimulation of the vestibular nerve modified t
he firing rates of neurons located in the same regions. Some neurons w
ith vestibular inputs received convergent signals from the abdominal v
agus nerve and could potentially mediate motion sickness-related vomit
ing. Others received convergent baroreceptor inputs and could act as a
substrate for some components of vestibulosympathetic reflexes. In co
ntrast, inspiratory neurons in the dorsal respiratory group received l
ittle vestibular input, suggesting that vestibulorespiratory reflexes
are mediated by cells located elsewhere.