Cardiopulmonary sympathetic afferent input does not require dorsal column pathways to excite C1-C3 spinal cells in rats

Effects of electrically stimulating the left stellate ganglion to activate cardiopulmonary sympathetic afferent (CPSA) fibers were determined on C1-C3 dorsal horn neurons in anaesthetized rats. Fifty-two of 53 dorsal horn neurons affected by CPSA stimulation were excited and one neuron was inhibited. In 6 experiments, dorsal columns and ventrolateral funiculi were sequentially lesioned to determine neuronal pathways involved in CPSA activation of C1-C3 neurons. In 6 additional experiments, spinal transection at rostral C1 was used to determine the contribution of supraspinal relays. We concluded that CPSA input to C1-C3 segments travelled bilaterally in ventrolateral pathways, and that supraspinal relays were not required for CPSA excitation of C1-C3 neurons. These results suggest that neurons in C1-C3 segments might play an important role in processing visceral spinal afferent information.