Opioid receptors are currently classified as µ (mu: mOP), δ (delta: dOP), κ (kappa: kOP) with
a fourth related non-classical opioid receptor for nociceptin/orphainin FQ, NOP. Morphine is …

Despite various advantages, opioid peptides have been limited in their therapeutic uses due
to the main drawbacks in metabolic stability, blood-brain barrier permeability, and …

The search for new peptides to be used as analgesics in place of morphine has been mainly
directed to develop peptide analogues or peptidomimetics having higher biological stability …

Narcotic analgesics such as morphine have been the mainstay for the treatment of severe
pain, although these drugs are associated with serious adverse effects, most notably …

The discovery of endogenous opioid peptides 25 years ago opened up a new chapter in
efforts to understand the origins and control of pain, its relationships to other biological …

A series of bifunctional peptides that act as agonists for δ and μ opioid receptors with δ
selectivity and as antagonist for neurokinin-1 (NK1) receptors were designed and …

A series of bifunctional peptides with opioid agonist and substance P antagonist bioactivities
were designed with the concept of overlapping pharmacophores. In this concept, the …

Two novel opioid analogues have been designed by substituting the native d-Ala residues
in position 2, 2′ of biphalin with two residues of d-penicillamine or l-penicillamine and by …

The area of multitarget compounds, joining two pharmacophores within one molecule, is a
vivid field of research in medicinal chemistry. Not only pharmacophoric elements are …

Natural residues of the dimeric opioid peptide Biphalin were replaced by the corresponding
homo-β3 amino acids. The derivative 1 containing hβ3 Phe in place of Phe showed good μ …