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MRI‐compatible procedures for behavioral pharmacology in squirrel monkeys
Author(s) -
Delatte Marcus Sherode,
Brimson Melanie,
Rohan Michael,
Kaufman Marc,
Bergman Jack
Publication year - 2007
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.21.5.a411
Subject(s) - squirrel monkey , morphine , medicine , anesthesia , core (optical fiber) , pharmacology , reinforcement , antagonist , lever , zoology , nuclear medicine , chemistry , psychology , anatomy , materials science , biology , physics , social psychology , receptor , quantum mechanics , composite material
We previously developed an MRI‐compatible chair in which monkeys could be seated comfortably, yet with head movement limited by a customized neck yoke and adjustable restraining plates. The aim of the present study was to evaluate the effects of morphine (0.1–1 mg/kg, i.m.) on behavior and core temperature in monkeys using this preparation. Subjects (n=3) were seated in a manner identical to that used for MRI studies and lever‐pressed for milk delivery under a 10‐response fixed‐ratio (FR 10) schedule of reinforcement. Milk was delivered by tubing through a bite bar that was in the subject's mouth throughout the session. Additionally, colonic temperature was measured with a rectal probe inserted prior to the session. Under control conditions, rates of responding averaged 2.6 ± 0.9 (SEM) resp/sec and core temperature averaged 38.1°C±0.1 (SEM). Morphine decreased responding in a dose‐related manner (0.1–1 mg/kg), without appreciably altering core temperature. Prior administration of the antagonist naltrexone (0.1 mg/kg) attenuated the effects of morphine by shifting the dose‐response function approximately 3‐fold rightward. Together, these data demonstrate that opioids have predictable effects on behavior and temperature under conditions that are especially designed for determining functional consequences of pharmacological treatment in laboratory subjects. (Supported by PHS grant DA03774 and DA7252).