Davies B T, Wellman P J
Department of Psychology, Texas A&M University, College Station 77843.
Physiol Behav. 1992 Sep;52(3):547-51. doi: 10.1016/0031-9384(92)90345-3.
alpha-Adrenergic receptors within the paraventricular hypothalamus (PVN) modulate feeding such that activation of alpha 2-adrenoceptors by drugs such as clonidine (CLON) increase feeding; whereas activation of alpha 1-adrenoceptors by drugs such as phenylpropanolamine (PPA) suppress feeding. Prior studies suggest that the feeding-stimulatory effect of alpha 2-adrenergic activation is a function of drug dose as well as the deprivation condition and adrenal status of the animal. Specifically, CLON's effects on feeding are greatest at low doses in food-satiated adrenally intact rats. Whether a similar profile is produced by alpha 1-adrenoceptor agonists such as PPA has not previously been explored. Thus, the present study provides a comparison of the effects on food intake of drug dose, deprivation condition, and adrenalectomy induced by these alpha 2- and alpha 1-adrenergic drugs. Accordingly, both adrenalectomized (ADX) as well as sham-control (SHAM) adult male rats underwent a series of 1-h feeding tests following administration of PPA (5, 10, 20 mg/kg, IP) as well as CLON (0.0125, 0.025, 0.05, 0.1 mg/kg, IP) under both deprived and nondeprived testing conditions. The results suggest that the deprivation condition, but not the surgical condition (ADX vs. SHAM), exerts the greatest overall effect on food intake following administration of alpha-adrenergic drugs.
下丘脑室旁核（PVN）内的α-肾上腺素能受体调节进食，使得可乐定（CLON）等药物激活α2-肾上腺素能受体会增加进食；而苯丙醇胺（PPA）等药物激活α1-肾上腺素能受体会抑制进食。先前的研究表明，α2-肾上腺素能激活的进食刺激作用是药物剂量以及动物的饥饿状态和肾上腺状态的函数。具体而言，在食物充足的肾上腺完整大鼠中，CLON对进食的影响在低剂量时最大。此前尚未探究过PPA等α1-肾上腺素能受体激动剂是否会产生类似的情况。因此，本研究比较了这些α2-和α1-肾上腺素能药物对药物剂量、饥饿状态和肾上腺切除所致食物摄入量的影响。相应地，将肾上腺切除（ADX）的成年雄性大鼠以及假手术对照（SHAM）成年雄性大鼠在剥夺和非剥夺测试条件下腹腔注射PPA（5、10、20mg/kg）以及CLON（0.0125、0.025、0.05、0.1mg/kg）后进行一系列1小时的进食测试。结果表明，饥饿状态而非手术状态（ADX与SHAM）对注射α-肾上腺素能药物后的食物摄入量产生最大的总体影响。
