Ventral striatal responses to reduced food intake in healthy animals and rats bearing small tumors

Anorexia is frequently observed during cancer and associated with increased morbidity and mortality. Our previous work has shown the presence of transcription factors in the ventral striatum of anorectic tumor-bearing rats. The aim of the present study was, therefore, to assess expression of neuropeptides, neurotransmitter-synthesizing enzymes and receptors in this structure. Morris hepatoma 7777 cells injected subcutaneously in Buffalo rats provoked a 15% reduction in food intake and 10% lower body weight when the tumor represented 1-2% of body mass. Mircorarrays and real-time PCR revealed increased ventral striatal prostaglandin D synthase expression in food-restricted animals compared to anorectic tumor-bearing rats. These findings indicate that reduced ventral striatal prostaglandin D synthesis underlies cancer-associated anorexia.癌症患者常出现厌食症，且该症状与更高的发病率和死亡率密切相关。我们此前的研究已证实，厌食性荷瘤大鼠的伏隔核（ventral striatum）中存在转录因子。因此，本研究旨在探究该脑区中神经肽、神经递质合成酶以及受体的表达情况。将莫里斯肝癌7777细胞（Morris hepatoma 7777）皮下注射至布法罗大鼠体内后，当肿瘤体积占大鼠体重的1%-2%时，受试大鼠进食量减少15%，体重降低10%。基因芯片（microarrays）与实时荧光定量PCR（real-time PCR）检测结果显示，与厌食性荷瘤大鼠相比，食物限制组大鼠的伏隔核内前列腺素D合酶（prostaglandin D synthase）表达水平显著升高。上述研究结果表明，伏隔核内前列腺素D合成水平降低是癌症相关性厌食症的潜在发病机制。