An imidazole based H-Phe-Phe-NH 2 peptidomimetic with anti-allodynic effect in spared nerve injury mice

Palladium-Catalyzed Aminocarbonylation of (Hetero)aryl Iodides with α-Amino Acid Esters as Nucleophiles

We report palladium-catalyzed aminocarbonylation of (hetero)aryl iodides with α-amino acid esters as nucleophiles. The synthesized N-capped α-amino acids are biologically important building blocks. The mild conditions provide products with high enantioselectivity at 80 °C in 35 min. The reactions are performed under air in a sealed vessel using chloroform as an in situ CO source. For the first time, regioselective carbonylation of histidine is also presented.

The amino-terminal heptapeptide of the algesic substance P provides analgesic effect in relieving chronic neuropathic pain

Of painful conditions, somatic pain of acute nociceptive origin can be effectively managed clinically, while neuropathic pain of chronic neuropathy origin is difficult to control. For molecules involved in pain sensation, substance P (SP) is algesic, exacerbating painful sensation, while its amino-terminal fragment, heptapeptide SP(1-7), confers biological activities different from its full-length parent neuropeptide precursor. We previously demonstrated SP(1-7) interaction with pain processing to alleviate chronic pain. Here we evaluated SP(1-7) and its C-terminal amidated analogue SP(1-7)amide, together with SP and opioid agonist DAMGO. We tested mouse behaviors of both acute somatic pain in tail-flick latency assay, and neuropathic pain in sciatic nerve injury model of chronic constriction injury (CCI). DAMGO produced dose-dependent analgesia for somatic pain as expected, so did both SP(1-7) and its analogue SP(1-7)amide, while SP yielded the opposite effect of algesia, in a phenomenon we termed 'contrintus', meaning 'opposite from within' to denote that two peptides of the same origin (SP and its metabolic fragment SP(1-7)) produced opposite effects. In CCI model, DAMGO showed a general reduction in allodynia sensitivity for both nerve-injured and normal paws, without selective effect for neuropathic pain, consistent with clinical observation that opioids are less effective for chronic neuropathic pain. On the other hand, both SP(1-7) and SP(1-7)amide displayed dose-dependent anti-allodynia effect that is selective for neuropathic pain. These findings suggest that SP(1-7) and its analogue may be useful for developing pharmaceuticals to treat neuropathic pain.

Endogenous Opiates and Behavior: 2018

This paper is the forty-first consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2018 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (2), the roles of these opioid peptides and receptors in pain and analgesia in animals (3) and humans (4), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (5), opioid peptide and receptor involvement in tolerance and dependence (6), stress and social status (7), learning and memory (8), eating and drinking (9), drug abuse and alcohol (10), sexual activity and hormones, pregnancy, development and endocrinology (11), mental illness and mood (12), seizures and neurologic disorders (13), electrical-related activity and neurophysiology (14), general activity and locomotion (15), gastrointestinal, renal and hepatic functions (16), cardiovascular responses (17), respiration and thermoregulation (18), and immunological responses (19).