TY - JOUR
T1 - Brain-targeted delivery of a leucine-enkephalin analogue by retrometabolic design
AU - Prokai-Tatrai, Katalin
AU - Prokai, Laszlo
AU - Bodor, Nicholas
PY - 1996/11/22
Y1 - 1996/11/22
N2 - A brain-targeted chemical delivery system (CDS) based on retrometabolic drug design was applied to a Leu-enkephalin analogue, Tyr-D-Ala-Gly-Phe-D- Leu (DADLE). The molecular architecture of the peptide CDS disguises its peptide nature from neuropeptide-degrading enzymes and provides lipophilic, bioreversible functions for the penetration through the blood-brain barrier. These functions were provided by a targetor, a 1,4-dihydrotrigonellyl group, on the N-terminus and a bulky, lipophilic ester group on the C-terminus. A spacer amino acid residue was also inserted between the targetor and the parent peptide to assure the release of DADLE by specific enzymes. Four CDSs were synthesized by segment-coupling method that proved to be superior to sequential elongation in obtaining this type of peptide conjugates. Intravenous injection of the compounds produced a significant and long- lasting response in rats monitored by the tail-flick latency measurements. CDSs having the bulkier cholesteryl group showed a better efficacy than those having the smaller 1-adamantaneethyl ester. The spacer was the most important factor to manipulate the rate of DADLE release and, thus, the pharmacological activity; proline as a spacer produced more potent analgesia than alanine. The antinociceptive effect of the CDSs was naloxone-reversible and methylnaloxonium-irreversible, confirming that central opiate receptors were solely responsible for mediating analgesia induced by the peptide CDS that delivered, retained, and then released the peptide in the brain.
AB - A brain-targeted chemical delivery system (CDS) based on retrometabolic drug design was applied to a Leu-enkephalin analogue, Tyr-D-Ala-Gly-Phe-D- Leu (DADLE). The molecular architecture of the peptide CDS disguises its peptide nature from neuropeptide-degrading enzymes and provides lipophilic, bioreversible functions for the penetration through the blood-brain barrier. These functions were provided by a targetor, a 1,4-dihydrotrigonellyl group, on the N-terminus and a bulky, lipophilic ester group on the C-terminus. A spacer amino acid residue was also inserted between the targetor and the parent peptide to assure the release of DADLE by specific enzymes. Four CDSs were synthesized by segment-coupling method that proved to be superior to sequential elongation in obtaining this type of peptide conjugates. Intravenous injection of the compounds produced a significant and long- lasting response in rats monitored by the tail-flick latency measurements. CDSs having the bulkier cholesteryl group showed a better efficacy than those having the smaller 1-adamantaneethyl ester. The spacer was the most important factor to manipulate the rate of DADLE release and, thus, the pharmacological activity; proline as a spacer produced more potent analgesia than alanine. The antinociceptive effect of the CDSs was naloxone-reversible and methylnaloxonium-irreversible, confirming that central opiate receptors were solely responsible for mediating analgesia induced by the peptide CDS that delivered, retained, and then released the peptide in the brain.
UR - http://www.scopus.com/inward/record.url?scp=0030471676&partnerID=8YFLogxK
U2 - 10.1021/jm960356e
DO - 10.1021/jm960356e
M3 - Article
C2 - 8941392
AN - SCOPUS:0030471676
SN - 0022-2623
VL - 39
SP - 4775
EP - 4782
JO - Journal of Medicinal Chemistry
JF - Journal of Medicinal Chemistry
IS - 24
ER -