Chu Xi, Ågmo Anders
Department of Psychology, University of Tromsø, Norway.
Department of Psychology, University of Tromsø, Norway.
Pharmacol Biochem Behav. 2016 May;144:33-44. doi: 10.1016/j.pbb.2016.02.008. Epub 2016 Feb 22.
Adrenergic α2 antagonists are known to enhance sexual incentive motivation and modify copulatory behavior while agonists are consistently inhibitory. However, many of the drugs employed in earlier studies were of modest specificity for the α2 receptor, and the importance of the different subtypes of this receptor remains completely unknown. In the present series of experiments we determined the effects on sexual incentive motivation and copulatory behavior of additional, highly specific compounds, as well as of agonists selective for each of the three subtypes of the α2 receptor. Sexual incentive motivation and copulatory behavior were evaluated in male rats in well established procedures. Among the α2 antagonists, RX 821002 reliably enhanced sexual incentive motivation while fluparoxan only had a modest effect. In large doses both drugs reduced copulatory behavior. The agonist S 18616 reduced both incentive motivation and copulation. None of the subtype selective agonists (BRL 44408, ARC 239, JP 1302) had any consistent effect. A peripheral α2 antagonist, L 659,066 was also ineffective. Even though there are some differences between α2 antagonists with regard to their effects on sexual incentive motivation and copulatory behavior it seems safe to conclude that antagonism of the adrenergic α2 receptor enhances motivation without any concomitant stimulation of copulatory behavior. It appears that antagonism of a single receptor subtype is insufficient for having this effect. Perhaps non-selective α2 antagonists could be used for the treatment of male sexual dysfunction.
已知肾上腺素能α2拮抗剂可增强性动机并改变交配行为，而激动剂则始终具有抑制作用。然而，早期研究中使用的许多药物对α2受体的特异性不强，该受体不同亚型的重要性仍然完全未知。在本系列实验中，我们确定了其他高特异性化合物以及对α2受体三种亚型各自具有选择性的激动剂对性动机和交配行为的影响。采用成熟的程序对雄性大鼠的性动机和交配行为进行评估。在α2拮抗剂中，RX 821002可靠地增强了性动机，而氟哌噻吨仅产生适度影响。大剂量时两种药物均减少了交配行为。激动剂S 18616同时降低了动机和交配行为。没有一种亚型选择性激动剂（BRL 44408、ARC 239、JP 1302）有任何一致的效果。外周α2拮抗剂L 659,066也无效。尽管α2拮抗剂在对性动机和交配行为的影响方面存在一些差异，但可以有把握地得出结论，肾上腺素能α2受体的拮抗作用可增强动机，而不会同时刺激交配行为。似乎单一受体亚型的拮抗作用不足以产生这种效果。或许非选择性α2拮抗剂可用于治疗男性性功能障碍。
