Nakashima M, Hashimoto H, Niho T
Department of Pharmacology, Hamamatsu University School of Medicine, Japan.
Jpn J Pharmacol. 1987 Dec;45(4):507-12. doi: 10.1254/jjp.45.507.
The effects of a newly synthesized compound, 2-[(5-chloro-2-methoxyphenyl)azo]-1H-imidazole (M6434) on alpha-adrenergic receptors were investigated by using the atria of normal and hypothyroid rats, rat vasa deferentia and canine arteries. M6434 showed a positive inotropic effect on rat left atria, which was suppressed by phentolamine but not by propranolol and reserpine. M6434 also showed a positive chronotropic effect on rat right atria. These positive inotropic and chronotropic effects of M6434 were enhanced in propylthiouracil-induced hypothyroid rats. M6434 caused contraction of rat vas deferens and increased its spontaneous movement. These effects on vas deferens were suppressed by phentolamine. M6434 induced contraction of canine arteries. The pD2 values for vasoconstrictive effects of M6434 on the aorta, pulmonary artery, renal artery and femoral artery were about equal to those of phenylephrine, and the intrinsic activity of M6434 was somewhat lower than that of phenylephrine. These results suggest that M6434 is an adrenergic alpha-agonist which is about as potent as phenylephrine and that M6434 has neither a beta-stimulating activity nor a catecholamine-releasing one.
通过使用正常和甲状腺功能减退大鼠的心房、大鼠输精管和犬动脉，研究了一种新合成的化合物2-[(5-氯-2-甲氧基苯基)偶氮]-1H-咪唑（M6434）对α-肾上腺素能受体的作用。M6434对大鼠左心房表现出正性肌力作用，酚妥拉明可抑制该作用，但普萘洛尔和利血平不能。M6434对大鼠右心房也表现出正性变时作用。丙硫氧嘧啶诱导的甲状腺功能减退大鼠中，M6434的这些正性肌力和正性变时作用增强。M6434引起大鼠输精管收缩并增加其自发运动。酚妥拉明可抑制M6434对输精管的这些作用。M6434诱导犬动脉收缩。M6434对主动脉、肺动脉、肾动脉和股动脉的血管收缩作用的pD2值与去氧肾上腺素的大致相等，且M6434的内在活性略低于去氧肾上腺素。这些结果表明，M6434是一种肾上腺素能α激动剂，其效力与去氧肾上腺素相当，且M6434既无β刺激活性也无儿茶酚胺释放活性。
