Spinal and supraspinal effects of pertussis toxin on opioid analgesia

• Published in: Pharmacology, biochemistry and behavior Vol. 49; no. 3; pp. 773 - 776
• Main Authors: Shah, Sukrut, Duttaroy, Alokesh, Davis, Trong, Yoburn, Byron C.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.11.1994; Elsevier Science
• Subjects: Analgesics; Analgesics - antagonists & inhibitors; Analgesics - pharmacology; Animals; Biological and medical sciences; Bordetella pertussis; Dose-Response Relationship, Drug; Etorphine; Etorphine - antagonists & inhibitors; Etorphine - pharmacology; Fentanyl; Fentanyl - antagonists & inhibitors; Fentanyl - pharmacology; Injections, Intraventricular; Injections, Spinal; Male; Medical sciences; Mice; Morphine; Morphine - antagonists & inhibitors; Morphine - pharmacology; Narcotic Antagonists - pharmacology; Narcotics - pharmacology; Neuropharmacology; Opioid analgesia; Opioid receptors; Pain Measurement - drug effects; Pertussis Toxin; Pharmacology. Drug treatments; Spinal analgesia; Spinal Cord - drug effects; Supraspinal analgesia; Virulence Factors, Bordetella - administration & dosage; Virulence Factors, Bordetella - pharmacology; Opioid receptors; Etorphine; Fentanyl; Morphine; Opioid analgesia; Spinal analgesia; Supraspinal analgesia; Pertussis toxin; Rodentia; Opiates; Islet activating protein; Cerebral ventricle; Narcotic analgesic; Intrathecal administration; Site of action; Analgesia; Vertebrata; Mammalia; Mouse; Animal; Second messenger; Intracerebral administration; Mechanism of action
• ISSN: 0091-3057; 1873-5177
• DOI: 10.1016/0091-3057(94)90101-5

The effects of in vivo pertussis toxin (PTX) treatment on the functional effects of opioid agonists were examined in the mouse. Mice were injected intracerebroventricularly (ICV), or intrathecally (IT), or IT and ICV with PTX, and dose-response studies of the antinociceptive action of systematic (SC) morphine, fentanyl, and etorpine were conducted 10 days later. IT PTX decreased the potency (≈ 4.5-fold) of morphine more than ICV administration (≈ 1.5-fold) whereas the combinationof IT and ICV administration produced an additive effect. When PTX was administered spinally and supraspinally, the potency of morphine, fentanyl, and etorphine was reduced similarly (≈ 5–7-fold), indicating that the effect of PTX does not vary considerably among agonists of different intrinsic efficacies. These studies indicate that in vivo PTX can reduce the potency of opioid agonists with different intrinsic efficacies, and that spinal mechanisms appear to be more sensitive to PTX treatment.