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Opioid effects on respiration and analgesia in turtles
Author(s) -
Johnson Stephen M.,
Sladky Kurt K.
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.755.11
Subject(s) - opioid , butorphanol , pharmacology , agonist , medicine , analgesic , nociception , morphine , anesthesia , nalbuphine , κ opioid receptor , receptor
A goal in veterinary medicine is to provide pain relief without respiratory depression. In non‐human mammals, several drug combinations provide analgesia and reverse opioid‐dependent respiratory depression. For reptiles, little is known with respect to opioid drug effects on respiration and nociception. Thus, breathing and responsiveness to noxious hindlimb thermal stimuli were measured in adult turtles before and after administration of drugs that activate specific opioid receptor subtypes or clinically‐relevant opioid drugs. Activation of mu‐ (MOR) or delta‐opioid (DOR) receptors decreased breathing by decreasing breath frequency; kappa‐opioid (KOR) receptor activation increased tidal volume. Activation of MOR (but not DOR or KOR) receptors increased hindlimb thermal withdrawal latencies. MOR agonists, such as morphine, methadone, and tramadol, produced analgesia, but also caused respiratory depression. In contrast, analgesic drugs, such as butorphanol (KOR agonist, MOR agonist/antagonist) and meperidine (MOR agonist) had no effect on nociception. These results show that not all analgesic drugs (that work in mammals) produce antinociception in turtles. Future studies will test (mammalian‐derived) drug combinations that produce opioid‐dependent analgesia and reverse respiratory depression in turtles. (Supported by NSF IOB 0517302, Morris Animal Foundation)