Petroff O A, Mattson R H, Behar K L, Hyder F, Rothman D L
Department of Neurology, Yale University, New Haven, CT 06520-8018, USA.
Ann Neurol. 1998 Dec;44(6):948-52. doi: 10.1002/ana.410440614.
Homocarnosine, a dipeptide of gamma-aminobutyric acid (GABA) and histidine, is thought to be an inhibitory neuromodulator synthesized in subclasses of GABAergic neurons. Homocarnosine is present in human brain in greater amounts (0.4-1.0 micromol/g) than in other animals. The antiepileptic drug vigabatrin increases human cerebrospinal fluid homocarnosine linearly with daily dose. By using 1H nuclear magnetic resonance spectroscopy, serial occipital lobe GABA and homocarnosine concentrations were measured in 11 patients started on vigabatrin. Daily low-dose (2 g) vigabatrin increased both homocarnosine and GABA. Larger doses of vigabatrin (4 g) further increased homocarnosine but changed GABA levels minimally. Seizure control improved with increasing homocarnosine and GABA concentrations. Patients whose seizure control improved with the addition of vigabatrin had higher mean homocarnosine, but the same mean GABA concentrations, than those whose seizure control did not improve. Increased homocarnosine may contribute to improved seizure control.
同型肌肽是γ-氨基丁酸（GABA）和组氨酸的二肽，被认为是在GABA能神经元亚类中合成的一种抑制性神经调节剂。同型肌肽在人脑中的含量（0.4 - 1.0微摩尔/克）比其他动物更高。抗癫痫药物vigabatrin可使人类脑脊液中的同型肌肽随日剂量呈线性增加。通过使用1H核磁共振波谱法，对11名开始使用vigabatrin的患者的枕叶GABA和同型肌肽浓度进行了连续测量。每日低剂量（2克）vigabatrin可使同型肌肽和GABA均增加。更大剂量的vigabatrin（4克）可进一步增加同型肌肽，但对GABA水平的影响最小。随着同型肌肽和GABA浓度的增加，癫痫控制情况得到改善。与癫痫控制未改善的患者相比，加用vigabatrin后癫痫控制得到改善的患者平均同型肌肽水平更高，但平均GABA浓度相同。同型肌肽增加可能有助于改善癫痫控制。
