van Giersbergen P L, de Lang H, de Jong W
Rudolf Magnus Institute for Pharmacology, Medical Faculty, State University of Utrecht, The Netherlands.
Can J Physiol Pharmacol. 1991 Mar;69(3):327-33. doi: 10.1139/y91-050.
The effect on blood pressure and heart rate of central administration of dynorphin A(1-13) and of beta-, gamma-, and alpha-endorphin related peptides was studied in urethane-anesthetized rats. Intracerebroventricular (i.c.v., 0.1-10 micrograms) administration of beta-endorphin resulted in a dose-dependent, naltrexone-reversible hypotension and bradycardia. N-terminally modified fragments of beta-endorphin did not reduce blood pressure and heart rate. On the other hand, a dose of 10 micrograms of beta-endorphin(1-27), which lacks the four C-terminal amino acid residues of beta-endorphin, induced a fall in blood pressure and had a biphasic effect on heart rate. These responses, however, were resistant to pretreatment with naltrexone. None of the fragments of beta-endorphin smaller than beta-endorphin(1-27) affected blood pressure when administered i.c.v. in a dose of 10 micrograms. A small transient bradycardia was observed after i.c.v. administration of 10 micrograms of beta-endorphin(1-26), alpha, and gamma-endorphin. The naltrexone-reversible bradycardic response of alpha- and gamma-endorphin was not present in des-tyrosine- and des-enkephalin-alpha- and gamma-endorphin and also not in alpha-endorphin(10-16) and gamma-endorphin(10-17). Upon i.c.v. administration (0.1-50 micrograms) a dose-dependent, naltrexone-reversible decrease in blood pressure and heart rate was induced by dynorphin A(1-13). The present data indicate a hypotensive influence of beta-endorphin, beta-endorphin(1-27), and dynorphin A(1-13), whereas other fragments of beta-endorphin had little or no effect on the cardiovascular parameters investigated.
在乌拉坦麻醉的大鼠中，研究了中枢给予强啡肽A（1-13）以及β-、γ-和α-内啡肽相关肽对血压和心率的影响。脑室内（i.c.v.，0.1-10微克）给予β-内啡肽导致剂量依赖性、纳曲酮可逆性低血压和心动过缓。β-内啡肽的N端修饰片段未降低血压和心率。另一方面，缺乏β-内啡肽四个C端氨基酸残基的10微克β-内啡肽（1-27）剂量可引起血压下降，并对心率产生双相作用。然而，这些反应对纳曲酮预处理具有抗性。当脑室内给予10微克剂量时，小于β-内啡肽（1-27）的β-内啡肽片段均未影响血压。脑室内给予10微克β-内啡肽（1-26）、α-内啡肽和γ-内啡肽后观察到短暂的小幅度心动过缓。去酪氨酸和去脑啡肽-α-和γ-内啡肽以及α-内啡肽（10-16）和γ-内啡肽（10-17）不存在α-和γ-内啡肽的纳曲酮可逆性心动过缓反应。脑室内给予（0.1-50微克）强啡肽A（1-13）可引起剂量依赖性、纳曲酮可逆性血压和心率下降。目前的数据表明β-内啡肽、β-内啡肽（1-27）和强啡肽A（1-13）具有降压作用，而β-内啡肽的其他片段对所研究的心血管参数几乎没有影响。
