【摘要】 目的:研究脑内P物质（substance P,SP）的心血管反应与去甲肾上腺素能系统的关系。方法:家兔脑室注射6-羟基多巴胺（6-hydroxydopamine,6-OHDA）10天后注射SP,记录平均动脉血压和心率的变化;放射受体测定法测定下丘脑及腹侧延髓中SP受体的密度和亲和力。结果:6-OHDA预处理后,下丘脑及腹侧延髓内NA的含量分别降低86.7％和77.0％,侧脑室注射SP的升压反应显著减弱。6-OHDA组下丘脑和腹侧延髓突触小体膜上SP受体总数B_max分别为（42±18）和（20±5）pmol·g^-1protein,显著低于对照组（108±5）和（35.9±2.2）pmol·g^-1protein,而6-OHDA组[¹²⁵I]SP对SP受体的平衡解离常数K_d[（0.029±0.001）,（0.015±0.003）nmol·L^-1]显著高于对照组[（0.015±0.004）,（0.014±0.006）nmol·L^-1]。结论:中枢去甲肾上腺素神经通路参与侧脑室注射SP的心血管反应。更多还原

【Abstract】 AIM: To study the role of norepinephrine system in the cardiovascular response to intracerebroventricular substance P (SP) in rabbit. METHODS: SP was given intracerebroventricularly in anesthetized rabbits pretreated with the catecholaminergic neurotoxin, 6-hydroxy-dopamine (6-OHDA). The density and affinity of SP receptors on synaptosomal membranes of the hypothala-mus and the ventral medulla of rabbits were determined by [125I]SP receptor assay. Arterial blood pressure and heart rate were recorded. RESULTS: Intracerebroventricular (icv) pretreatment of rabbits with 6-OHDA , reduced norepinephrine in the hypothalamus (by 86.7 %) and in the ventral medulla (by 77.0 %) respectively . The pressor response and tachycardia of these rabbits to icv SP (3.55 nmol · kg-1) were attenuated. The density and the affinity of SP receptors in the hypothalamus and the ventral medulla of 6-OHDA-lesioned rabbits were decreased. The Bmax(pmol·g-1 protein) of SP receptors in hypothalamus and the ventral medulla are 108±5, 35.9±2.2 in control group, and 42±18, 20±5 in 6-OHDA-lesioned rabbits, respectively. Kd (nmol· L-1) of SP receptors in the two regions are 0.015±0.004, 0.014 ± 0.006 in control group and 0.029 ±0.001, 0.015± 0.003 in 6-OHDA group. There is a significant difference of Bmax (P < 0.01) and Kd ( P < 0.01, P < 0.05) in both regions between 6-OHDAid groups and control groups. CONCLUSION: The results suggested that central norepinephrine pathways are involved in the cardiovascular response to icv SP.更多还原