Papka R E, Urban L
Department of Anatomy, University of Kentucky, Lexington 40536.
Acta Physiol Hung. 1987;69(3-4):459-68.
This report is intended as an overview of the distribution, origin and sensitivity to capsaicin of substance P-immunoreactive (SP-I) primary afferent cardiac nerves. Immunohistochemical and physiological methods were employed to compare the presence and density of these nerve fibers in the guinea pig and rat hearts. SP-I fibers are numerous in the guinea pig heart including the parietal pericardium, atria, ventricles, valves, coronary arteries and around intrinsic cardiac ganglion cells. The rat heart contains few SP-I fibers. Vagotomy does not influence the number of intensity of immunoreactive fibers in the guinea pig heart. By stimulating the atrium or ventricle and recording from the second or third thoracic dorsal roots Ad1, Ad2 and C fibers were demonstrated in the atria, but only Ad fibers in the guinea pig ventricle; in addition, only Ad fibers were recorded from the vagus nerves. Only Ad1 fibers were demonstrated in the rat heart. Treatment with capsaicin depletes the SP-I and decreases the conduction velocity of C-fibers and some Ad2 fibers in the guinea pig heart. We suggest that SP-I primary afferent nerve fibers are unmyelinated (C-type) or small myelinated (Ad2-type) nerves in the guinea pig heart and that their cell bodies of origin are predominantly in dorsal root ganglia.
本报告旨在概述P物质免疫反应性（SP-I）心脏初级传入神经的分布、起源及对辣椒素的敏感性。采用免疫组织化学和生理学方法比较豚鼠和大鼠心脏中这些神经纤维的存在情况及密度。豚鼠心脏中SP-I纤维丰富，包括壁层心包、心房、心室、瓣膜、冠状动脉及心内神经节细胞周围。大鼠心脏中SP-I纤维很少。迷走神经切断术不影响豚鼠心脏中免疫反应性纤维的数量或强度。通过刺激心房或心室并记录第二或第三胸段背根，在心房中证实有Aδ1、Aδ2和C纤维，但在豚鼠心室中仅证实有Aδ纤维；此外，从迷走神经仅记录到Aδ纤维。在大鼠心脏中仅证实有Aδ1纤维。辣椒素处理可耗尽豚鼠心脏中的SP-I，并降低C纤维和一些Aδ2纤维的传导速度。我们认为，豚鼠心脏中SP-I初级传入神经纤维是无髓鞘（C型）或小髓鞘（Aδ2型）神经，其起源的细胞体主要位于背根神经节。
