Gietzen D W, Beverly J L
Department of Physiological Sciences, School of Veterinary Medicine, University of California, Davis 95616.
Am J Physiol. 1992 Oct;263(4 Pt 2):R885-90. doi: 10.1152/ajpregu.1992.263.4.R885.
Ingestion of imbalanced amino acid diets (IMB) has been associated with a decrease in norepinephrine (NE) concentration in the prepyriform cortex (PPC), an area essential for the anorectic response to IMB. Decreased NE could result from activity-induced release (and subsequent metabolism) of the transmitter. If activity of the NE system is important in the rat's anorectic response to IMB, reduced NE activity should result in increased IMB intake. Therefore, the feeding response to IMB was measured after injecting clonidine (Clon) into the PPC to inhibit NE release. At 3 and 6 h after Clon (1.0 and 1.5 micrograms/rat) injections, IMB intake was increased from 69 (the usual response to IMB in untreated animals) to > 100% of control intake. Effective injection sites did not include the gustatory neocortex, an area important for conditioned taste aversions. Thus activation of the NE system in the PPC may be associated with the initial reduced intake of IMB, suggesting that NE activity in the PPC has a role in the neural mechanisms that subserve recognition of amino acid deficiency.
摄入不均衡氨基酸饮食（IMB）与梨状前皮质（PPC）中去甲肾上腺素（NE）浓度降低有关，PPC是对IMB产生厌食反应所必需的区域。NE浓度降低可能是由于该递质的活动诱导释放（以及随后的代谢）所致。如果NE系统的活动在大鼠对IMB的厌食反应中很重要，那么NE活性降低应导致IMB摄入量增加。因此，在向PPC注射可乐定（Clon）以抑制NE释放后，测量对IMB的进食反应。在注射Clon（1.0和1.5微克/只大鼠）后3小时和6小时，IMB摄入量从69（未处理动物对IMB的通常反应）增加至对照摄入量的>100%。有效的注射部位不包括味觉新皮质，味觉新皮质是对条件性味觉厌恶很重要的区域。因此，PPC中NE系统的激活可能与最初IMB摄入量减少有关，这表明PPC中的NE活性在有助于识别氨基酸缺乏的神经机制中起作用。
