Objective: To study the effect of baicalin on synaptosomal adenosine triphosphatase (ATPase) and lactate dehydrogenase (LDH) and its regulatory effect on the adenylate cyclase (AC)/cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) signaling pathway in rats with attention deficit hyperactivity disorder (ADHD).
Methods: A total of 40 SHR rats were randomly divided into five groups: ADHD model, methylphenidate hydrochloride treatment (0.07 mg/mL), and low-dose (3.33 mg/mL), medium-dose (6.67 mg/mL), and high-dose (10 mg/mL) baicalin treatment (n=8 each). Eight WKY rats were selected as normal control group. Percoll density gradient centrifugation was used to prepare brain synaptosomes and an electron microscope was used to observe their structure. Colorimetry was used to measure the activities of ATPase and LDH in synaptosomes. ELISA was used to measure the content of AC, cAMP, and PKA.
Results: Compared with the normal control group, the ADHD model group had a significant reduction in the ATPase activity, a significant increase in the LDH activity, and significant reductions in the content of AC, cAMP, and PKA (P<0.05). Compared with the ADHD model group, the methylphenidate hydrochloride group and the medium- and high-dose baicalin groups had a significant increase in the ATPase activity (P<0.05), a significant reduction in the LDH activity (P<0.05), and significant increases in the content of AC, cAMP, and PKA (P<0.05). Compared with the methylphenidate hydrochloride group, the high-dose baicalin group had significantly greater changes in these indices (P<0.05). Compared with the low-dose baicalin group, the high-dose baicalin group had a significant increase in the ATPase activity (P<0.05); the medium- and high-dose baicalin groups had a significant reduction in the LDH activity (P<0.05) and significant increases in the content of AC, cAMP, and PKA (P<0.05). Compared with the medium-dose baicalin group, the high-dose baicalin group had a significant increase in the ATPase activity (P<0.05).
Conclusions: Both methylphenidate hydrochloride and baicalin can improve synaptosomal ATPase and LDH activities in rats with ADHD. The effect of baicalin is dose-dependent, and high-dose baicalin has a significantly greater effect than methylphenidate hydrochloride. Baicalin exerts its therapeutic effect possibly by upregulating the AC/cAMP/PKA signaling pathway.
目的: 研究黄芩苷对注意缺陷多动障碍（ADHD）模型大鼠脑突触体腺苷三磷酸（ATP）酶、乳酸脱氢酶（LDH）的影响及对腺苷酸环化酶（AC）/环磷酸腺苷（cAMP）/蛋白激酶A（PKA）信号通路的调控作用。
方法: 将40只SHR大鼠随机分为模型组、盐酸哌甲酯组（0.07 mg/mL）、黄芩苷低（3.33 mg/mL）、中（6.67 mg/mL）、高剂量组（10 mg/mL），每组8只，另设WKY大鼠8只为正常对照组。Percoll密度梯度离心法制备脑突触体，电镜观察突触体结构；运用比色法检测突触体ATP酶、LDH活性；运用ELISA法检测突触体内AC、cAMP、PKA的含量。
结果: 与正常对照组比较，模型组大鼠脑突触体存在ATP酶活性降低、LDH活性升高及AC、cAMP、PKA含量降低的改变（P < 0.05）。与模型组比较，盐酸哌甲酯及黄芩苷中、高剂量均能显著升高ADHD模型大鼠脑突触体内ATP酶活性（P < 0.05），降低LDH活性（P < 0.05），并显著提高AC、cAMP、PKA含量（P < 0.05）。与盐酸哌甲酯组比较，高剂量黄芩苷治疗ADHD模型大鼠对改善上述各指标水平的效果更为显著（P < 0.05）。与黄芩苷低剂量组比较，黄芩苷高剂量组ATP酶活性显著升高（P < 0.05）；黄芩苷中、高剂量组LDH活性显著降低，AC、cAMP、PKA含量均显著升高（P < 0.05）。与黄芩苷中剂量组比较，黄芩苷高剂量组ATP酶活性显著升高（P < 0.05）。
结论: 盐酸哌甲酯及黄芩苷均能改善ADHD模型大鼠脑突触体ATP酶、LDH活性；黄芩苷的作用与剂量存在相关性，且高剂量黄芩苷较盐酸哌甲酯效果更为显著；黄芩苷可能是通过上调AC/cAMP/PKA信号通路发挥治疗作用。