The purpose of this morphological study was to investigate the relations between meridians, acupoints and viscera using neuroanatomical tracers. The labeled areas of the spinal ganglia, sympathetic chain ganglia, spinal cord and the brain projecting to the heart, Nei-Kuan (EH-6) and Shen-Men (He-7) were observed following injection of WGA-HRP and pseudorabies virus (PRV). The results were as follows. Overlapping bilaterally labeled ganglion areas after heart, Nei-Kuan (EH-6) or Shen-Men (He-7) injection of WGA-HRP were found in middle cervical, stellate and T4 sympathetic and T2-T6 spinal ganglia. In brain, labeled neurons from all three sites were found in the A1 noradrenalin cell group/C1 adrenalin cell group/caudoventrolateral reticular n., n. tractus solitarius, n. ambiguus, rostroventrolateral n., C3 adrenaline cell group, raphe obscurus n., raphe pallidus n., raphe magnus n., lateral paragigantocellular reticular n., locus coeruleus, subcoeruleus n., Kolliker-Fuse n., A5 cell group, central gray matter, paraventricular hypothalamic n. and arcuate hypothalamic n.. In conclusion, these morphological results suggest that the interrelationship of acupoints (Nei-Kuan and Shen-Men) and viscera (heart) may be related to the central autonomic centers of the spinal cord and brain.