The upper cervical spinal region functions as an intra-spinal controller of thoracic spinal reflexes and contributes to neuronal regulation of the ischemic myocardium. Our objective was to determine whether stimulation of the C2 cervical spinal cord (SCS) of rats modified the input signal at the thoracic spinal cord when cardiac ischemia-sensitive (sympathetic) afferents were activated by transient occlusion of the left anterior descending coronary artery (CoAO). Changes in c-Fos expression were used as an index of neuronal activation within the spinal cord and brainstem. The pattern of substance P (SP) release, a putative nociceptive transmitter, was measured using antibody-coated microprobes. Two SCS protocols were used: reactive SCS, applied concurrently with intermittent CoAO and pre-emptive, sustained SCS starting 15 min prior to and continuing during the repeated intermittent CoAO. CoAO increased SP release from laminae I-II in the T4 spinal cord above resting levels. Intermittent SCS with CoAO resulted in greater levels of SP release from deeper laminae IV-VII in T4 than CoAO alone. In contrast, SP release from laminae I-II was inhibited when CoAO was applied during pre-emptive, sustained SCS. Pre-emptive SCS likewise reduced cFos expression in the T4 spinal cord (laminae I-V) and nucleus tractus solitarius but increased expression in the intermediolateral cell column of T4 compared to CoAO alone. These results suggest that pre-emptive SCS from the high cervical region modulates sensory afferent signaling from the ischemic myocardium.