Journal Article

Preliminary Findings of Structure and Expression of Opioid Receptor Genes in a Peregrine Falcon (Falco peregrinus), a Snowy Owl (Bubo scandiacus), and a Blue-fronted Amazon Parrot (Amazona aestiva)

Silversides, David W., Fitzgerald, Guy, Duhamelle, Alexis, Raiwet, Diana L., Langlois, Isabelle

2018

Overview

To further knowledge of the physiology of opioid receptors in birds, the structure and expression of the μ-, δ-, and κ-opioid receptor genes were studied in a peregrine falcon (Falco peregrinus), a snowy owl (Bubo scandiacus), and a blue-fronted Amazon parrot (Amazona aestiva). Tissue samples were obtained from birds that had been euthanatized for poor release prognosis or medical reasons. Samples were taken from the brain (telencephalon, thalamus, pituitary gland, cerebellum, pons, medulla oblongata, mesencephalon), the spinal cord and dorsal root ganglions, and plantar foot skin. Messenger RNA was recovered, and reverse transcription polymerase chain reaction (RT-PCR) was performed to generate complementary DNA (cDNA) sequences. Gene structures were documented by directly comparing cDNA sequences with recently published genomic sequences for the peregrine falcon and the blue-fronted Amazon parrot or by comparisons with genomic sequences of related species for the snowy owl. Structurally, the avian μ-opioid receptor messenger RNA (mRNA) species were complex, displaying differential splicing, alternative stop codons, and multiple polyadenylation signals. In comparison, the structure of the avian κ-receptor mRNA was relatively simple. In contrast to what is seen in humans, the avian δ-receptor mRNA structure was found to be complex, demonstrating novel 3-prime coding and noncoding exons not identified in mammals. The role of the δ-opioid receptor merits further investigation in avian species.

• Publisher: The Association of Avian Veterinarians,Association of Avian Veterinarians
• Subject: Amazon aestiva / Amazona / Amazona - genetics / Amazona - metabolism / analgesia / Animals / avian / blue-fronted Amazon parrot / Bubo scandiacus / cerebellum / complementary DNA / exons / Falco peregrinus / Falconiformes - genetics / Falconiformes - metabolism / Female / gene expression / Genetic Variation / humans / Male / medulla oblongata / messenger RNA / opioid / ORIGINAL STUDIES / Original Study / parrots / peregrine falcon / physiology / pituitary gland / prognosis / receptor / receptors / Receptors, Opioid - genetics / Receptors, Opioid - metabolism / reverse transcriptase polymerase chain reaction / snowy owl / Species Specificity / spinal cord / stop codon / Strigiformes - genetics / Strigiformes - metabolism / thalamus