Biochemical and electrophysiological properties of SR 57746A, a new, potent 5-HT1A receptor agonist

Summary— SR 57746A (1-[2-(naphth-2-yl) ethyl]-4-(3-trifluoromethylphenyl)-1, 2, 5, 6 tetra-hydropyridine hydrochloride) binds competitively, and with high affinity (K_i = 2.0 ± 0.7 nM) to 5-HT_1A receptors from rat hippocampus in vitro , but has much less affinity for other 5-HT receptor subtypes (IC₅₀ > 650 nM). SR 57746A produces a concentration-dependent inhibition of forskolin-stimulated adenylate cyclase activity in rat hippocampal homogenates, with a maximal effect identical to that of 8-OH-DPAT, suggesting that SR 57746A behaves as a full agonist in tthis experimental model. SR 57746A potently displaces [³H]8-OH-DPAT binding to rat hippocampal membranes ex vivo , with an ID₅₀ of 11.1 mg/kg po, 30 min after administration, and 2.8 mg/kg po, 2 h after administration. This effect of SR 57746A is long-lasting (at least 24 hours at 10 mg/kg po). SR 57746A does not modify the levels of 5-HT or DA in various brain areas, but decreases the concentrations of 5-HIAA, and increases those of DOPAC, HVA and 3-MT. Following iv administration, SR 57746A (0.095 to 0.25 mg/kg) inhibits the spontaneous firing of dorsal raphe neurones, but does not modify the activity of DA neurones in the substantia nigra or ventral tegmental area. Thus, SR 57746A is a potent, selective and full agonist at 5-HT_1A receptors in vitro and vivo.     

针刺足三里穴磁共振功能成像的初步探讨

目的　采用磁共振功能成像 (fMRI)技术了解针刺足三里穴时脑的反应 ,为针灸治疗的中枢机制提供实验依据。方法　利用fMRI -BOLD技术 ,获取脑血流变化的实验数据 ,利用感兴趣区 (ROI)分析方法 ,获得针刺足三里穴时脑功能变化正相关系数(CC)的脑功能图。结果　针刺右侧足三里穴引起视丘下部 ,同侧室旁核和双侧颞叶、中央后回脑血流增加 ,且右侧感兴趣区范围较左侧广。结论　针刺足三里穴可引起植物神经中枢和颞叶变化 ,与中医经络学说认为足三里穴有治疗胃肠疾病和改善精神及睡眠状态的作用密切联系。针刺足三里穴时能引起双侧特定脑皮层的反应 ,但以同侧为主 ,表明经络独特感传道的存在 ,且与周围神经不尽相同。     

Mechanism of human accommodation as analyzed by nonlinear finite element analysis

Results of nonlinear finite element analysis support the Schachar theory of accommodation and demonstrate that the long-held Helmholtz theory of accommodation is impossible.