Stofer W D, Fatherazi S, Horn J P
Department of Physiology, University of Pittsburgh, School of Medicine, PA 15261.
J Auton Nerv Syst. 1990 Nov;31(2):141-51. doi: 10.1016/0165-1838(90)90071-p.
The effects of preganglionic sympathetic nerve stimulation and exogenous agents upon vascular tone were observed in hindlimb preparations of pithed adult bullfrogs. Repetitive electrical stimulation of the sympathetic C, but not the B, system elicited arterial vasoconstriction and reduced blood flow in vascular beds supplying the sartorius muscle and the skin. Close-arterial injections of epinephrine and neuropeptide Y each mimicked neurogenic vasoconstriction. After close-arterial injection of phentolamine, an alpha-adrenergic antagonist, the maximal effects of nerve stimulation were delayed in onset and reduced in magnitude, but not eliminated. Pretreatment with phentolamine blocked the vasoconstriction caused by injection of epinephrine, and produced a mild reduction in responses to neuropeptide Y. These observations demonstrate the vasomotor function of the sympathetic C system and they support the hypothesis that neuropeptide Y and epinephrine function as cotransmitters in postganglionic C neurons.
在去脑成年牛蛙的后肢标本中观察了节前交感神经刺激和外源性药物对血管张力的影响。对交感神经C系统而非B系统进行重复电刺激可引起动脉血管收缩，并减少供应缝匠肌和皮肤的血管床中的血流量。动脉内注射肾上腺素和神经肽Y均可模拟神经源性血管收缩。在动脉内注射α-肾上腺素能拮抗剂酚妥拉明后，神经刺激的最大效应在起效时间上延迟，且幅度减小，但并未消除。酚妥拉明预处理可阻断注射肾上腺素引起的血管收缩，并使对神经肽Y的反应略有降低。这些观察结果证明了交感神经C系统的血管运动功能，并支持神经肽Y和肾上腺素在节后C神经元中作为共同递质发挥作用的假说。
