Mathy M J, Thoolen M J, Timmermans P B, van Zwieten P A
Br J Pharmacol. 1984 Feb;81(2):255-62. doi: 10.1111/j.1476-5381.1984.tb10072.x.
The effect of the imidazolidine Sgd 101/75 (2-[2-methylindazol-4-imino]-imidazolidine HCl) on blood pressure, as well as its alpha-adrenoceptor agonist activity and affinity for these receptors, were examined in various animal preparations. After both intravenous administration to conscious spontaneously hypertensive rats and intravenous injection or infusion via the vertebral artery in chloralose-anaesthetized cats, Sgd 101/75 (1-10 mg kg-1) elicited pressor responses. Intracisternal application of Sgd 101/75 (1 mg kg-1) to chloralose-anaesthetized cats did not affect blood pressure. In the pithed rat and pithed cat the vasopressor responses to i.v. Sgd 101/75 were effectively antagonized by prazosin (0.1-1.0 mg kg-1, i.v.) but much less by yohimbine (1 mg kg-1, i.v.). Sgd 101/75 proved a less potent and less selective displacing agent of [3H]-clonidine- and [3H]-prazosin-binding in rat brain membranes than clonidine. The results suggest that Sgd 101/75 is a selective alpha 1-adrenoceptor agonist, devoid of any centrally or peripherally mediated hypotensive activity; this is probably caused by the low capacity of Sgd 101/75 for stimulating alpha 2-adrenoceptors.
在多种动物制剂中研究了咪唑烷Sgd 101/75（2-[2-甲基吲唑-4-亚氨基]-咪唑烷盐酸盐）对血压的影响及其α-肾上腺素能受体激动剂活性和对这些受体的亲和力。在清醒的自发性高血压大鼠静脉给药以及在氯醛糖麻醉的猫中通过椎动脉静脉注射或输注后，Sgd 101/75（1-10mg/kg）引起升压反应。向氯醛糖麻醉的猫脑池内应用Sgd 101/75（1mg/kg）不影响血压。在去脑大鼠和去脑猫中，静脉注射Sgd 101/75引起的血管升压反应可被哌唑嗪（0.1-1.0mg/kg，静脉注射）有效拮抗，但被育亨宾（1mg/kg，静脉注射）拮抗的程度要小得多。与可乐定相比，Sgd 101/75在大鼠脑膜中对[3H]-可乐定和[3H]-哌唑嗪结合的置换作用效力较低且选择性较差。结果表明，Sgd 101/75是一种选择性α1-肾上腺素能受体激动剂，没有任何中枢或外周介导的降压活性；这可能是由于Sgd 101/75刺激α2-肾上腺素能受体的能力较低所致。
