1.The HRP labeled method was used to study the segmental distribution of sympathetic afferentneurons of the heart.10%-20% HRP 150ul solution was injected around the left coronary artery of18 cats.The HRP labeled cells were observed in the C_8-T_(10)spinal ganglions

therefore the segmentaldistribution of sympathetic afferent neurons of the heart were in C_8-T_(10)spinal cord.2.The segmental distribution of cardiac nerve's afferent neurons was studied

30% HRP 15μlwas injected into the cardiac nerve of 18 cats.The HRP labeled cells were observed in the C_8-T_9 spinalganglions.3.CB-HRP 10μl was injected into the medium and inferior cardiac nerves.The cardiac nerve'sfibers project into T_(1-5)spinal cord

the HRP labeled fibers were observed in Ⅲ-Ⅶ lamina of spinalcord

and there were connections with Ⅲ

Ⅳ

Ⅴ

Ⅵ

Ⅶ laminas.4.The segmental distribution of sympathetic afferent neurons of heart and cardiac nerve

projec-tion of the cardiac nerve the Ⅲ-Ⅶ laminae of spinal cord and the connection of fibers in the Ⅲ-Ⅶlaminae were the morphologic foundations of referred pain and the heart disease.(tachycordia

anginaetc.)treated with acupuncture.