Nedergaard O A
Department of Pharmacology, School of Medicine, Odense University, Denmark.
Pharmacol Toxicol. 1994 Jan;74(1):43-9. doi: 10.1111/j.1600-0773.1994.tb01072.x.
The inhibitory affinity of dopexamine hydrochloride to postsynaptic adrenoceptors, cholinoceptors, 5-hydroxytryptamine and histamine receptors was studied in rabbit isolated aorta. Dopexamine (10(-7)-10(-5) M) antagonized competitively the contractions of rabbit aorta evoked by noradrenaline (pA2: 6.60). Neither cocaine plus corticosterone nor cocaine, corticosterone plus propranolol altered the inhibition (pA2: 6.77 and 6.63, respectively). The antagonism of dopexamine against noradrenaline-evoked contractions was the same after 1 and 4 hr of pretreatment with dopexamine. In the presence of cocaine plus corticosterone, dopexamine antagonized the contractions evoked by phenylephrine (pA2: 6.94). Removal of endothelium did not influence this antagonism (pA2: 7.06). Dopexamine (10(-7)-10(-5) M) did not antagonize the contractions of aorta evoked by histamine (3 x 10(-7)-6 x 10(-5) M) and by 5-hydroxytryptamine (3 x 10(-7)-3 x 10(-4) M). Dopexamine (10(-8 and 10(-7) M) did not alter the contractions of endothelium-free aorta evoked by carbachol. Dopexamine (10(-7)-10(-5) M) slightly enhanced the contractions of aorta evoked by potassium (10(-2)-5.5 x 10(-2) M). These results suggest that dopexamine is an alpha 1-adrenoceptor antagonist. Furthermore, dopexamine has no affinity to cholinoceptors, histamine and 5-hydroxytryptamine (5-HT2) receptors and is apparently not a calcium antagonist.
在兔离体主动脉中研究了盐酸多培沙明对突触后肾上腺素能受体、胆碱能受体、5-羟色胺和组胺受体的抑制亲和力。多培沙明（10⁻⁷ - 10⁻⁵ M）竞争性拮抗去甲肾上腺素引起的兔主动脉收缩（pA₂：6.60）。可卡因加皮质酮或可卡因、皮质酮加普萘洛尔均未改变这种抑制作用（pA₂分别为6.77和6.63）。用多培沙明预处理1小时和4小时后，多培沙明对去甲肾上腺素引起的收缩的拮抗作用相同。在可卡因加皮质酮存在的情况下，多培沙明拮抗苯肾上腺素引起的收缩（pA₂：6.94）。去除内皮不影响这种拮抗作用（pA₂：7.06）。多培沙明（10⁻⁷ - 10⁻⁵ M）不拮抗组胺（3×10⁻⁷ - 6×10⁻⁵ M）和5-羟色胺（3×10⁻⁷ - 3×10⁻⁴ M）引起的主动脉收缩。多培沙明（10⁻⁸和10⁻⁷ M）不改变卡巴胆碱引起的无内皮主动脉的收缩。多培沙明（10⁻⁷ - 10⁻⁵ M）轻微增强钾（10⁻² - 5.5×10⁻² M）引起的主动脉收缩。这些结果表明多培沙明是一种α₁ - 肾上腺素能受体拮抗剂。此外，多培沙明对胆碱能受体、组胺和5-羟色胺（5-HT₂）受体没有亲和力，显然也不是钙拮抗剂。
