To determine if electrical stimulation of autonomic nerves could excite nonadrenergic inhibitory motor pathways in the guinea pig respiratory system in vivo, we studied the effects of electrical stimulation of the cervical vagi and sympathetic nerve trunks on pressure changes (Pp) within an isolated, fluid-filled cervical tracheal segment which reflected changes in trachealis muscle tone. We preserved the innervation and circulation of the segment as evidenced by a rise in Pp with vagus nerve stimulation and a fall in Pp with intravenous isoproterenol.
Sarah E. Chesrown, C. S. Venugopalan, Warren M. Gold, Jeffrey M. Drazen