RT Journal Article
SR Electronic
T1 In Vivo and In Vitro Evidence of Blood-Brain Barrier Transport of a Novel Cationic Arginine-Vasopressin Fragment 4-9 Analog
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 561
OP 568
VO 290
IS 2
A1 Shuichi Tanabe
A1 Yasuyuki Shimohigashi
A1 Yasuhisa Nakayama
A1 Takashi Makino
A1 Tsugumi Fujita
A1 Takeru Nose
A1 Gozoh Tsujimoto
A1 Teruo Yokokura
A1 Mikihiko Naito
A1 Takashi Tsuruo
A1 Tetsuya Terasaki
YR 1999
UL http://jpet.aspetjournals.org/content/290/2/561.abstract
AB The blood-brain barrier (BBB) transport and metabolism of a novel arginine-vasopressin fragment 4-9 [AVP4-9, isoelectric point; (pI) = 9.2] analog, that is, cationic AVP4-9 (C-AVP4-9, PI = 9.8), were examined in vivo and in vitro. At 45 min after an i.v. administration to mice, the cerebrum-to-plasma concentration ratios of 35S-labeled AVP4-9 and 125I-labeled C-AVP4-9were 0.103 and 0.330 ml/g cerebrum, respectively, and the BBB permeation clearances were 1.47 × 10−4 and 3.10 × 10−4 ml/min/g cerebrum, respectively. In the in vitro study using mouse brain capillary endothelial cells immortalized by SV40 infection (MBEC4), the acid-resistant binding values of35S-labeled AVP4-9 and 125I-labeled C-AVP4-9 to MBEC4 at 120 min were 0.93 and 1.95 μl/mg protein (as the cell/medium ratios), respectively.35S-labeled AVP4-9 showed two-phase saturable acid-resistant binding, and its half-saturation constants (KD) were 3.8 nM (high affinity) and 45.7 μM (low affinity). 125I-labeled C-AVP4-9showed single-phase saturable acid-resistant binding, with aKD value of 16.4 μM. The acid-resistant binding of 125I-labeled C-AVP4-9 was significantly dependent on temperature and medium osmolarity. The acid-resistant binding of 125I-labeled C-AVP4-9was inhibited by dancylcadaverine, phenylarsine oxide (endocytosis inhibitors), 2,4-dinitrophenol (a metabolic inhibitor), and AVP4-9, poly(l-lysine), and protamine (cationic substances), but not by poly(l-glutamic acid) (an anionic peptide) and the V1 and V2vasopressin receptor antagonists. In addition, the conversion of C-AVP4-9 to AVP4-9 in the cerebral homogenate was confirmed by HPLC and mass spectrometry. The present results demonstrate that C-AVP4-9 is transported through the BBB more effectively than AVP4-9, via absorptive-mediated endocytosis, and that C-AVP4-9 is converted to the neuroactive parent peptide, AVP4-9, in the cerebrum. The American Society for Pharmacology and Experimental Therapeutics