Courtice G P
School of Physiology and Pharmacology, University of New South Wales, Kensington, Sydney, Australia.
J Auton Nerv Syst. 1991 May;33(3):231-8. doi: 10.1016/0165-1838(91)90023-v.
The effects of neuropeptide-Y (NPY) and galanin (GAL) on the autonomic control of heart rate were investigated in the anaesthetised toad, Bufo marinus. Both vagosympathetic trunks were sectioned to prevent reflex changes in heart rate, and the cardiac responses to electrical stimulation of either the vagal or sympathetic fibres to the heart assessed. Intravenous, bolus doses of 10 or 20 micrograms (2 or 4 nmol) NPY and 5 or 10 micrograms (1.5 or 3 nmol) GAL caused pronounced pressor responses but small direct changes in heart rate. Pulse intervals measured after peptide administration were within 5% of control values. All doses of both peptides caused inhibition of action of the cardiac vagus nerves, the maximum inhibition observed in response to 20 micrograms NPY: mean 49.5 +/- 14% (SEM). No significant changes in cardiac sympathetic nerve action were observed. It is concluded that NPY and GAL have similar, important cardiovascular actions in the toad. Similarities between the responses of toads and mammals to NPY suggest a phylogenetic conservation of function for this peptide.
在麻醉的海蟾蜍（Bufo marinus）中研究了神经肽Y（NPY）和甘丙肽（GAL）对心率自主控制的影响。切断双侧迷走交感干以防止心率的反射性变化，并评估心脏对迷走神经或交感神经纤维电刺激的反应。静脉注射大剂量的10或20微克（2或4纳摩尔）NPY和5或10微克（1.5或3纳摩尔）GAL可引起明显的升压反应，但心率的直接变化较小。给予肽后测量的脉搏间期在对照值的5%以内。两种肽的所有剂量均导致心脏迷走神经作用受到抑制，对20微克NPY反应时观察到的最大抑制：平均49.5±14%（标准误）。未观察到心脏交感神经作用有显著变化。得出的结论是，NPY和GAL在蟾蜍中具有相似的重要心血管作用。蟾蜍和哺乳动物对NPY反应的相似性表明该肽在功能上具有系统发育保守性。
