DAGO ([D-Ala2,N-Me-Phe4,Gly-ol]enkephalin) specifically reverses apomorphine-induced increase in rearing and grooming behaviors in the mouse.
The effects of intracerebroventricular injections (10 microliters) of the mu-selective opioid peptide DAGO on apomorphine (0.1, 0.56, 1.0 and/or 3.0 mg/kg)-induced motor activity were investigated in the mouse using multi-dimensional behavioral analyses. A lower dose (0.1 mg/kg) of apomorphine failed to significantly affect motor activity, whilst higher doses (0.56, 1.0 and 3.0 mg/kg) of the drug produced a marked increase in linear locomotion, circling, rearing and/or grooming behaviors. DAGO (0.003 and 0.01 micrograms) did not significantly affect different behaviors. DAGO (0.01 micrograms) antagonized the apomorphine (1.0 mg/kg)-induced increase in behaviors such as rearing and grooming. However, DAGO (0.003 or 0.01 micrograms) did not affect behaviors induced by a 3.0 mg/kg dose of apomorphine. Furthermore, the effects of DAG]O on apomorphine-induced behaviors were fully reversed by treatment with the mu-selective alkylating agent beta-FNA (beta-funaltrexamine) (5.0 micrograms). These results suggest that mu opioid receptors play a principal role in the apomorphine-induced increase in rearing and grooming behaviors.
Ukai
M
M
Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Meijo University, Nagoya, Japan.
Toyoshi
T
T
Kameyama
T
T
D000818:Animals; D001058:Apomorphine / Q000008:administration & dosage / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D004745:Enkephalins / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D006120:Grooming / Q000187:drug effects*; D007276:Injections, Intraventricular; D051379:Mice; D008815:Mice, Inbred Strains; D009043:Motor Activity / Q000187:drug effects; D009271:Naltrexone / Q000031:analogs & derivatives / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D011957:Receptors, Opioid / Q000187:drug effects; D017450:Receptors, Opioid, mu
D004745:Enkephalins; D009292:Narcotic Antagonists; D011957:Receptors, Opioid; D017450:Receptors, Opioid, mu; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D009271:Naltrexone; C024524:beta-funaltrexamine; D001058:Apomorphine