levorphanol and Body-Weight

Topics: Administration, Oral; Animals; Biotransformation; Body Weight; Codeine; Dealkylation; Dextropropoxyphene; Dogs; Guinea Pigs; Humans; Injections, Subcutaneous; Levorphanol; Meperidine; Methadyl Acetate; Morphine; Narcotics; Rabbits; Rats; Substance Withdrawal Syndrome; Substance-Related Disorders; Time Factors

Prolyl-leucyl-glycinamide (PLG) at a low dose (10 ng/mouse) administered by an intracerebroventricular (i.c.v.) injection did not affect levorphanol analgesia, but PLG at higher doses (10 and 100 micrograms/mouse) and alpha-melanocyte-stimulating hormone (alpha-MSH) (10 ng/mouse) antagonized levorphanol analgesia. Development of levorphanol tolerance was facilitated by 10 ng/mouse of PLG, unaffected by 10 micrograms/mouse of PLG, but antagonized by 100 micrograms/mouse of PLG and 10 ng/mouse of alpha-MSH. The effect of PLG on levorphanol dependence was assessed by changes in body weight and temperature during naloxone-induced withdrawal. PLG (10 ng/mouse) facilitated the development of levorphanol dependence, but 10 micrograms/mouse of PLG had no effect. PLG (100 micrograms/mouse) antagonized development of levorphanol dependence. PLG at doses of 10 and 100 micrograms/mouse precipitated withdrawal in levorphanol-dependent mice. alpha-MSH (10 ng/mouse) antagonized development of levorphanol dependence as evidenced by an increase in the ED50 of naloxone required to induce withdrawal jumping. These results indicate that PLG and alpha-MSH affected levorphanol-induced analgesia, tolerance and dependence in a qualitatively similar manner to their effect on morphine-induced analgesia, tolerance and dependence.

Topics: Analgesia; Animals; Body Temperature; Body Weight; Dose-Response Relationship, Drug; Drug Tolerance; Humans; Levorphanol; Male; Melanocyte-Stimulating Hormones; Mice; MSH Release-Inhibiting Hormone; Naloxone; Substance Withdrawal Syndrome; Substance-Related Disorders

Topics: Animals; Body Temperature; Body Weight; Dextrorphan; Diet; Feeding Behavior; Levorphanol; Male; Morphinans; Rats; Stereoisomerism; Time Factors

Topics: Adrenal Glands; Animals; Body Weight; Brain; Drug Tolerance; Epinephrine; Female; Growth; Humans; Levorphanol; Methadone; Monoamine Oxidase Inhibitors; Morphine; Morphine Dependence; Norepinephrine; Organ Size; Rats; Stimulation, Chemical; Substance Withdrawal Syndrome; Substance-Related Disorders; Thebaine; Time Factors