Martel C L, Mackic J B, McComb J G, Ghiso J, Zlokovic B V
Department of Neurological Surgery, Childrens Hospital Los Angeles, USC School of Medicine 90033, USA.
Neurosci Lett. 1996 Mar 15;206(2-3):157-60. doi: 10.1016/s0304-3940(96)12462-9.
An intracarotid brain infusion/capillary depletion technique was used in guinea pigs to examine cerebral capillary sequestration and transport into brain parenchyma of sA beta 1-40 and sA beta 1-42, synthetic peptides identical to two forms of the amyloid beta peptide found in Alzheimer's disease lesions: the 40 residue form, found primarily in vascular deposits, and the 42 residue form, found primarily in senile plaques. The peptides crossed well into the brain parenchyma via a specific transport mechanism for which sA beta 1-40 had an approximately two-fold greater affinity than sA beta 1-42. There was significant capillary sequestration of sA beta 1-40, but retention by the microvasculature of sA beta 1-42 was negligible. These data suggest that the level of the 40 residue peptide in cerebral vasculature and of the 42 residue peptide in parenchyma could be regulated by blood-brain barrier sequestration and transport of their respective circulating precursors.
在豚鼠中采用颈内脑灌注/毛细血管耗竭技术，以检测脑毛细血管对淀粉样β蛋白1-40（sAβ1-40）和淀粉样β蛋白1-42（sAβ1-42）的隔离作用以及它们向脑实质的转运情况。这两种合成肽与在阿尔茨海默病病变中发现的两种形式的淀粉样β肽相同：40个残基的形式主要存在于血管沉积物中，42个残基的形式主要存在于老年斑中。这些肽通过一种特定的转运机制顺利进入脑实质，sAβ1-40对该转运机制的亲和力比sAβ1-42大约高两倍。sAβ1-40存在显著的毛细血管隔离现象，但sAβ1-42在微血管中的滞留可忽略不计。这些数据表明，脑微血管系统对各自循环前体的隔离和转运可能调节脑实质中40个残基肽和42个残基肽的水平。
