Plasma concentrations of nociceptin/orphanin FQ: comparison of levels after general and neuraxial anesthesia for arthroscopic knee surgery

Avian opioid peptides: evolutionary considerations, functional roles and a challenge to address critical questions

The present review considers the putative hormonal opioid peptides in birds. In birds and all other vertebrates, there are four opioid related genes encoding a series of peptides. These genes are, respectively, proenkephalin (PENK), prodynorphin (PDYN), pronociceptin (PNOC) and proopiomelanocortin (POMC). Proenkephalin (PENK) encodes Met- and Leu-enkephalin together with peptides containing met enkephalin motifs in birds, mammals and reptiles. Proopiomelanocortin (POMC) encodes β endorphin together with adrenocorticotropic hormone (ACTH), and melanocyte stimulating hormone (MSH). Prodynorphin (PDYN) encoding dynorphins A and B with α- and β-neoendorphins together intermediate polypeptides across the vertebrates. Pronociceptin (PNOC) encodes nociceptin together with possibly putative avian nocistatin and a non-opioid peptide derived from the C terminal of pronociceptin. There is a high degree of identity in the sequences of enkephalin peptides, dynorphin-A and B and nociceptin in birds and, to a less extent, across vertebrates. The opioid peptides exert effects related to pain together with other biological actions such as growth/development acting via a series of opioid receptors. What is unclear, particularly in birds, is the biological roles and interactions (additivity, antagonistic and synergistic) for the individual opioid peptides, the processing of the prohormones in different tissues and the physiological relevance of the different peptides and, particularly, of the circulating forms.

Endogenous opiates and behavior: 2013

This paper is the thirty-sixth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2013 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.