Activity of aortic chemoreceptors during electrical stimulation of the stellate ganglion in the cat.

1. In anaesthetized cats, action potentials from aortic chemoreceptors were recorded during electrical stimulation of preganglionic sympathetic fibres to the decentralized right stellate ganglion. The rate of discharge in afferents in the ipsilateral but not in the contralateral aortic nerve increased when stimulus frequency was 4/sec or higher.2. The post-ganglionic fibres in the stimulated pathway originate in the right stellate ganglion. They leave the ganglion in the caudal limb of the ansa subclavia, and the results suggest that the ipsilateral aortic nerve and its branches distribute sympathetic fibres as well as afferents to aortic bodies.3. In contrast, the rate of discharge of chemoreceptor fibres in the contralateral aortic nerve fell as blood pressure increased during sympathetic stimulation. Sympathetic pathways to the aortic bodies can maintain or increase chemoreceptor discharge during hypertension elicited by sympathetic activation.