Boyano M C, Bodega G, Arilla E
Department of Biochemistry and Molecular Biology, Medical School, University of Alcalá, Madrid, Spain.
Peptides. 1993 Sep-Oct;14(5):925-31. doi: 10.1016/0196-9781(93)90068-r.
Short (90 min)-, mid (5 days)-, and long-term (15 days) ammonium acetate (5 mmol/kg IP) administration decreased the number of specific [125I][Tyr11]somatostatin receptors in synaptosomes from the frontoparietal cortex without changing the affinity constant. Administration of ammonium acetate did no affect the levels of somatostatin-like immunoreactivity in the frontoparietal cortex. The administration of a single dose of N-carbamyl-L-glutamate (1 mmol/kg) plus L-arginine (1 mmol/kg) 1 h before the last administration of ammonium acetate totally blocked the inhibitory effects of the latter on somatostatin receptor number in the frontoparietal cortex synaptosomes. N-Carbamyl-L-glutamate plus L-arginine alone had no observable effect on the somatostatinergic system. The decrease in the number of somatostatin receptors induced by ammonium acetate might reflect decreased target cell sensitivity to somatostatin, a phenomenon that could contribute to the depressed neuronal excitability induced by ammonia in the rat frontoparietal cortex.
短期（90分钟）、中期（5天）和长期（15天）腹腔注射醋酸铵（5 mmol/kg）可减少额叶顶叶皮质突触体中特异性[125I][Tyr11]生长抑素受体的数量，而不改变亲和常数。醋酸铵的给药不影响额叶顶叶皮质中生长抑素样免疫反应性的水平。在最后一次给予醋酸铵前1小时给予单剂量的N-氨甲酰-L-谷氨酸（1 mmol/kg）加L-精氨酸（1 mmol/kg）可完全阻断后者对额叶顶叶皮质突触体中生长抑素受体数量的抑制作用。单独的N-氨甲酰-L-谷氨酸加L-精氨酸对生长抑素能系统没有可观察到的影响。醋酸铵诱导的生长抑素受体数量减少可能反映了靶细胞对生长抑素的敏感性降低，这一现象可能导致大鼠额叶顶叶皮质中氨诱导的神经元兴奋性降低。
