Alper R H, Zink M H
Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City.
J Pharmacol Exp Ther. 1994 Apr;269(1):305-12.
A conditioned emotional response paradigm was established to determine the roles of adrenergic and nonadrenergic neurotransmitters in the hemodynamic responses during stress in conscious rats. The alpha adrenoceptor antagonists, prazosin (alpha-1-selective) or phentolamine (nonselective), blocked the stress-induced increase in mean arterial pressure (MAP), but not the increase in iliac blood flow or the decrease in iliac vascular resistance. Stress-induced iliac dilation was eliminated by the nonselective beta-adrenoceptor antagonist sotalol. In rats treated with prazosin plus sotalol, stress increased MAP but did not alter iliac vascular resistance. In contrast, stress did not increase MAP after complete adrenergic blockade with phentolamine plus sotalol yet did decrease iliac vascular resistance. Bilateral adrenal demedullation (ADM) did not affect the hemodynamic responses during stress, but ganglionic blockade eliminated them in both intact rats and in rats subjected to ADM. The stress-induced vasodilation in rats with ADM was not altered by sotalol, in direct contrast to intact rats. Finally, in rats with ADM, neither atropine nor sotalol (individually or when combined) altered any of the hemodynamic responses elicited by stress. The data suggest that during a conditioned emotional response: 1) adrenal catecholamines are not critical to the hemodynamic responses; 2) the increase in MAP is mediated by alpha-1 and alpha-2 adrenoceptor activation and 3) most critically, the hindquarter vasodilation is mediated by the release of neural adrenergic and nonadrenergic, noncholinergic factors.
建立了一种条件性情绪反应范式，以确定肾上腺素能和非肾上腺素能神经递质在清醒大鼠应激期间血液动力学反应中的作用。α肾上腺素能受体拮抗剂哌唑嗪（α-1选择性）或酚妥拉明（非选择性）可阻断应激诱导的平均动脉压（MAP）升高，但不能阻断髂血流量增加或髂血管阻力降低。非选择性β肾上腺素能受体拮抗剂索他洛尔可消除应激诱导的髂血管扩张。在用哌唑嗪加索他洛尔治疗的大鼠中，应激会增加MAP，但不会改变髂血管阻力。相比之下，在用酚妥拉明加索他洛尔完全阻断肾上腺素能后，应激不会增加MAP，但会降低髂血管阻力。双侧肾上腺髓质切除术（ADM）不影响应激期间的血液动力学反应，但神经节阻断可消除完整大鼠和接受ADM的大鼠的血液动力学反应。与完整大鼠形成直接对比的是，索他洛尔不会改变ADM大鼠应激诱导的血管舒张。最后，在ADM大鼠中，阿托品和索他洛尔单独或联合使用均不会改变应激引起的任何血液动力学反应。数据表明，在条件性情绪反应期间：1）肾上腺儿茶酚胺对血液动力学反应并不关键；2）MAP升高是由α-1和α-2肾上腺素能受体激活介导的；3）最关键的是，后肢血管舒张是由神经肾上腺素能和非肾上腺素能、非胆碱能因子的释放介导的。
