Head-shake distributions during self-maintained dependence on morphine, methadone, and l-alpha-acetylmethadol (LAAM) in the rat.
Adult female Sprague-Dawley rats were prepared with chronic cortical and muscle electrodes and i.v. cannulas, made tolerant to and physically dependent on morphine, and trained to level press for i.v. morphine self-injections to maintain dependence. Methadone or l-alpha-acetylmethadol (LAAM) was then substituted for morphine in some of these rats. During self-maintained dependence on either morphine or methadone, head shakes appeared and increased in frequency before lever pressing for self-injections. In contrast, there were fewer head shakes during LAAM dependence, which were evenly distributed over the entire duration of the interinjection interval. These findings suggest a relationship between head-shake distributions, drug-seeking behavior and the pharmacodynamics of these three narcotics.
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D005260:Female; D006801:Humans; D008691:Methadone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology*; D008692:Methadyl Acetate / Q000008:administration & dosage / Q000494:pharmacology*; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology*; D009021:Morphine Dependence / Q000503:physiopathology*; D051381:Rats; D012646:Self Administration; D019966:Substance-Related Disorders / Q000503:physiopathology*
D009020:Morphine; D008692:Methadyl Acetate; D008691:Methadone