The reasons which led to the search in the brain for substances with morphine-like actions
are discussed. Two pentapeptides, methionine-enkephalin and leucine-enkephalin, were …

Three series of nociceptin (NC)-related peptides were synthesized and their abilities (i) to
bind to the NC sites expressed in mouse forebrain membranes,(ii) to inhibit the electrically …

The C terminus of endomorphin-2 (EM-2) analogues (Tyr-Pro-Phe-NH-X) was modified with
aromatic, heteroaromatic, or aliphatic groups (X= phenethyl, benzyl, phenyl, naphthyl …

We have investigated the influence of physico-chemical parameters (chemical structure and
lipophilicity), biochemical properties (catabolism, affinity for 3 H-etorphine binding sites and …

Pain relief achieved by co-administration of drugs acting at different targets is more effective
than that obtained with conventional MOR selective agonists usually associated to relevant …

Morphine and D-Ala2-Met-enkephalin as well as other opioids suppress potassium-
stimulated release of 3H-labeled dopamine from nervous tissue of two marine invertebrates …

The purpose of these investigations was to estimate the relative potency, receptor affinity,
and agonist efficacy of several selective delta opioid agonist peptides of diverse structure …

Since the discovery of endogenous opiate-like substances, numerous and ever increasing
numbers of studies have been performed which highlight the importance of these …

The highly selective non-equilibrium μ-antagonist β-funaltrexamine (β-FNA) produced a
maximal 20-fold shift in the IC 50 for the μ-agonist morphine on the guinea-pig ileum …

Human semen contains large amounts of authentic β-endorphin and other B-endorphin
immunoreactive peptides. To eliminate the non-specific effects of semen in the B-endorphin …