Banks W A, Kastin A J
VA Medical Center, New Orleans, LA.
Peptides. 1994 Jan;15(1):23-9. doi: 10.1016/0196-9781(94)90165-1.
Tyr-MIF-1 (Tyr-Pro-Leu-Gly-NH2) and MIF-1 (Pro-Leu-Gly-NH2) are endogenous peptides that can exert opiate-related actions on the CNS after peripheral administration. We found that Tyr-MIF-1 radioactively labeled at the tyrosine was transported across the blood-brain barrier (BBB) in the direction of brain to blood by a saturable system. Transport occurred equally well when the tetrapeptide was labeled with 125I or when it was labeled with 3H. [3H]MIF-1 and [3H]morphine were not transported out of the CNS but were retained by the brain after intracerebroventricular injection. Both [3H]MIF-1 and [3H]morphine entered the brain after i.v. injection, with [3H]MIF-1 crossing the BBB by a mechanism that was partially saturable. The entry rate and accumulation of radioactivity by the brain was 50-100 times greater after the i.v. injection of [3H]MIF-1 than after [3H]morphine. The results show that Tyr-MIF-1 labeled with either 3H or 125I can serve equally well for the measurement of transport across the BBB, that MIF-1 has relatively substantial and rapid access from the blood to the CNS by directly crossing the BBB, and that the BBB can differentially regulate the exchange of related substances between the CNS and blood.
酪氨酰 - 促黑素细胞激素 -1（Tyr - Pro - Leu - Gly - NH2）和促黑素细胞激素 -1（Pro - Leu - Gly - NH2）是内源性肽，外周给药后可对中枢神经系统发挥与阿片类相关的作用。我们发现，酪氨酸放射性标记的酪氨酰 - 促黑素细胞激素 -1通过一个可饱和系统以从脑到血的方向穿过血脑屏障（BBB）。当四肽用125I标记或用3H标记时，转运效果相同。脑室内注射后，[3H]促黑素细胞激素 -1和[3H]吗啡不会从中枢神经系统转运出来，而是被脑保留。静脉注射后，[3H]促黑素细胞激素 -1和[3H]吗啡均进入脑内，[3H]促黑素细胞激素 -1通过一种部分可饱和的机制穿过血脑屏障。静脉注射[3H]促黑素细胞激素 -1后脑对放射性的摄取率和积累量比注射[3H]吗啡后高50 - 100倍。结果表明，用3H或125I标记的酪氨酰 - 促黑素细胞激素 -1在测量血脑屏障转运方面效果相同，促黑素细胞激素 -1可通过直接穿过血脑屏障相对大量且快速地从血液进入中枢神经系统，并且血脑屏障可不同程度地调节中枢神经系统与血液之间相关物质的交换。
