title: Opioid receptors in the ventral tegmental area contribute to stress-induced analgesia in the formalin test for tonic pain.
abstract: Exposure to stress can induce analgesia in the formalin test for tonic pain. Here, we report that blockade of opioid receptors by bilateral infusions of naltrexone methylbromide (NMB) (0.1 microgram/0.5 microliter/side) in the ventral tegmental area (VTA) in the midbrain can reduce stress-induced analgesia in this test. These findings indicate that endogeneous opioids act in the VTA to mediate stress-induced analgesia in tonic pain.
authors.affiliation: Department of Psychology, Concordia University, Montreal, Canada.
authors.forename: N
authors.initials: N
authors.lastname: Altier
authors.forename: J
authors.initials: J
authors.lastname: Stewart
mesh_terms: D000698:Analgesia; D000818:Animals; D004597:Electroshock; D005557:Formaldehyde; D008297:Male; D009271:Naltrexone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D010147:Pain Measurement / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D011957:Receptors, Opioid / Q000502:physiology*; D013315:Stress, Psychological / Q000523:psychology*; D017557:Ventral Tegmental Area / Q000502:physiology*
chemical_list: D009292:Narcotic Antagonists; D011957:Receptors, Opioid; D005557:Formaldehyde; D009271:Naltrexone