Urban L, Papka R E
J Auton Nerv Syst. 1985 Apr;12(4):321-31. doi: 10.1016/0165-1838(85)90047-5.
Primary afferent and substance P (SP)-immunoreactive nerve fibers of the guinea pig and rat heart were investigated by physiological and immunohistochemical methods. Immunohistochemistry revealed abundant SP-positive fibers in the guinea pig atria, with fewer in the ventricles. Only an occasional fiber was seen in the rat atrium or ventricle. Sectioning the vagus nerve did not noticeably influence the supply of SP-immunoreactive nerve fibers in the guinea pig heart. When the atria or ventricles were stimulated, afferent nerve fiber activity was recorded from the second and third thoracic dorsal roots. In guinea pig atria 3 types of fibers were identified on the basis of conduction velocities: A delta 1, A delta 2 and C fibers. Only A delta fibers were identified in the ventricle. By vagal recordings, A delta fibers were demonstrated but a C fiber response could not be shown in this nerve. SP-immunoreactivity in primary afferent fibers was depleted by the neurotoxin capsaicin. Capsaicin treatment also caused a reduction in the conduction velocity of small diameter myelinated A delta 2 (by 29%) and unmyelinated C fibers (by 46%). In the rat heart, evidence for A delta 2 or C fibers was not found. These results indicate that primary afferent and SP-immunoreactive fibers are numerous in guinea pig heart, but few in the rat. It is concluded that most of these fibers have their cell bodies of origin in the dorsal root ganglia.
采用生理学和免疫组织化学方法，对豚鼠和大鼠心脏的初级传入神经纤维和P物质（SP）免疫反应性神经纤维进行了研究。免疫组织化学显示，豚鼠心房中有大量SP阳性纤维，心室中较少。在大鼠心房或心室中仅偶尔可见纤维。切断迷走神经对豚鼠心脏中SP免疫反应性神经纤维的供应没有明显影响。当刺激心房或心室时，从第二和第三胸段背根记录传入神经纤维活动。在豚鼠心房中，根据传导速度鉴定出3种纤维类型：Aδ1、Aδ2和C纤维。在心室中仅鉴定出Aδ纤维。通过迷走神经记录，证实存在Aδ纤维，但在此神经中未显示出C纤维反应。神经毒素辣椒素使初级传入纤维中的SP免疫反应性耗竭。辣椒素处理还导致小直径有髓Aδ2纤维（降低29%）和无髓C纤维（降低46%）的传导速度降低。在大鼠心脏中，未发现Aδ2或C纤维的证据。这些结果表明，豚鼠心脏中初级传入神经纤维和SP免疫反应性纤维数量众多，但大鼠中较少。得出的结论是，这些纤维大多数起源于背根神经节的细胞体。
