T. G. Waldrop

Localization of the cells of origin for primary afferent fibers supplying the gallbladder of the cat

Horseradish peroxidase was utilized to study the distribution of afferent fibers from the gallbladder in cats. The afferent cell bodies were found in the nodose ganglion and T4 to L1 dorsal root ganglia.

Activation of visceral thin-fiber afferents increases respiratory output in cats

Respiratory responses to chemical activation of thin-fiber afferents from the stomach and the gallbladder were measured in anesthetized cats. Capsaicin or bradykinin applied to the serosal surface of either the stomach or the gallbladder elicited increases in breathing and phrenic nerve activity. Transection of the cervical vagi or the carotid sinus nerves had no effect on these responses. However, the respiratory responses to visceral stimulation were abolished by bilateral transection of the splanchnic nerves. We conclude that activation of thin-fiber afferents from the stomach and gallbladder causes a reflex increase in respiratory output. The initial afferent limb of this reflex is via the splanchnic nerves.

Respiratory responses to chemical activation of left ventricular receptors

Respiratory responses to chemical activation of receptors in the left ventricle were measured in anesthetized cats. Application of capsaicin (10 micrograms) or bradykinin (500 ng) to the serosal surface of the left ventricle caused increases in phrenic nerve activity and in arterial pressure. These responses persisted after cervical vagotomy and after bilateral transection of the carotid sinus nerves. Bilateral stellate ganglionectomy abolished the respiratory responses to capsaicin and bradykinin. In addition, stellate ganglionectomy prevented the arterial pressure response to bradykinin; however, a slight increase in arterial pressure occurred with application of capsaicin. It is concluded that activation of sympathetic afferents originating in the left ventricle causes an increase in respiratory output.