Simpson C W, Baile C A, Krabill L F
J Comp Physiol Psychol. 1975 Jan;88(1):176-82. doi: 10.1037/h0076199.
Feeding responses of sheep and steers were compared following intraventricular injection of alpha-adrenergic agonists and antagonists in 2-hr. tests. In sheep, injection of the alpha-agonist 1-norepinephrine (1-NE) (140-1,120 nmoles) increased feed intakes 288% and 388% compared with intakes following synthetic cerebrospinal fluid. This response was blocked by the alpha-antagonist phenoxybenzamine, whereas the antagonist alone decreased feed intake. The beta-adrenergic antagonist propranolol did not modify the 1-NE response. A purer but weaker alpha-agonist, 1-phenylephrine, also resulted in increased feed intake that was blocked by phenoxybenzamine. In contrast to the feeding responses of sheep, 1-NE caused hypophagia in steers, reducing intakes as much as 58% in 2-hr. tests over doses ranging 42-27,800 nmoles. Phenoxybenzamine blocked the 1-NE-induced hypophagia in steers; when injected alone, it increased feed intakes 181% of control values. Changes in feeding following 1-NE injections are probably not attributable to changes in temperature, fat mobilization, or stupor. The data support the hypothesis of an alpha-adrenergic-coded system for feeding in sheep and for satiety in steers.
在2小时的试验中，对脑室注射α-肾上腺素能激动剂和拮抗剂后的绵羊和公牛的采食反应进行了比较。在绵羊中，与注射合成脑脊液后的采食量相比，注射α-激动剂1-去甲肾上腺素（1-NE）（140 - 1120纳摩尔）使采食量分别增加了288%和388%。这种反应被α-拮抗剂酚苄明阻断，而单独使用该拮抗剂会降低采食量。β-肾上腺素能拮抗剂普萘洛尔并未改变1-NE的反应。一种更纯但效力较弱的α-激动剂1-去氧肾上腺素也导致采食量增加，且该增加被酚苄明阻断。与绵羊的采食反应不同，1-NE导致公牛食欲减退，在2小时的试验中，剂量范围为42 - 27800纳摩尔时，采食量减少高达58%。酚苄明阻断了1-NE诱导的公牛食欲减退；单独注射时，它使采食量增加至对照值的181%。1-NE注射后采食的变化可能并非归因于温度、脂肪动员或昏迷状态的改变。这些数据支持了关于绵羊采食和公牛饱腹感存在α-肾上腺素能编码系统的假说。
