Linked Life Data

16803861

Source:http://linkedlifedata.com/resource/pubmed/id/16803861

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2006-9-26
pubmed:abstractText
The endogenous mu-opioid receptor agonist, endomorphin (EM)-1, cannot be delivered into the central nervous system (CNS) in sufficient quantity to elicit analgesia when given systemically because it is severely restricted by the blood-brain barrier (BBB). To improve the physicochemical characteristics of EM-1 and subsequently achieve greater BBB permeation, we synthesized a series of EM-1 analogs by combining successful chemical modifications, including N-terminal cationization, C-terminal chloro-halogenation, and unnatural amino acid (d-Ala, Sar, and d-Pro-Gly) substitutions in position 2. Presently, their binding and bioassay activity, lipophilicity, stability, and antinociceptive activity were determined and compared. Guanidino-addition and chloro-halogenation attenuated the mu-receptor affinity to some extent, but they demonstrated differences in the influence on stability. It appeared that guanidino-addition contributed to brain stability enhancement for the greater part, whereas chloro-halogenation together with amino acid substitutions in position 2 was of more importance for the stability enhancement in serum than in brain. Determination of the octanol/buffer coefficient revealed that chloro-halogenation did compromise the decreased lipophilicity caused by guanidino-addition, and introduction of d-Ala as well as d-Pro-Gly, but not Sar, in place of l-Pro(2), also increased the overall lipophilicity to some extent. Among the peptides tested, intracerebroventricular injection of guanidino-[d-Ala(2), p-Cl-Phe(4)]EM-1 showed the strongest analgesia, being 3 times more potent than the parent peptide. We also found that in comparison with EM-1, the four d-Ala-containing tetrapeptides and the chloro-halogenated d-Pro-Gly-containing pentapeptide elicited significant and prolonged central-mediated analgesia upon subcutaneous administration, indicating that more peptides reached the CNS, eliciting greater analgesic effect.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0022-3565
pubmed:author
pubmed:issnType
Print
pubmed:volume
319
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
308-16
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Utilization of combined chemical modifications to enhance the blood-brain barrier permeability and pharmacological activity of endomorphin-1.
pubmed:affiliation
Department of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tianshui South Road, Lanzhou 730000, People's Republic of China.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't