Effect of adenosine receptor agonists and antagonists on morphine-induced catalepsy in mice.
Effects of adenosine receptor agonists and antagonists on morphine-induced catalepsy in mice were investigated. The adenosine agonists, NECA (5'-N-ethylcarboxamidoadenosine) and S-PIA (S(+)-N6-(2-phenylisopropyl)adenosine) in doses which did not induce any response, increased the cataleptogenic effect produced by morphine. However, the morphine response was decreased and increased by the lower and higher doses of the adenosine receptor agonist, CHA (N6-cyclohexyladenosine), respectively. The adenosine receptor antagonist, theophylline, decreased, but 8-phenyltheophylline increased, the response induced by morphine. Naloxone inhibited the catalepsy induced by morphine or morphine + NECA but not that induced by NECA alone. It is concluded that adenosine A2 receptor activation increases, while adenosine A1 receptor stimulation decreases, the morphine cataleptogenic response. The response to morphine may be mediated through opioid and adenosine receptor mechanisms.
Zarrindast
M R
MR
Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Iran.
Iraie
F
F
Heidari
M R
MR
Mohagheghi-Badi
M
M
D019830:Adenosine-5'-(N-ethylcarboxamide) / Q000494:pharmacology; D000818:Animals; D002375:Catalepsy / Q000139:chemically induced / Q000503:physiopathology / Q000517:prevention & control*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D008297:Male; D051379:Mice; D009020:Morphine / Q000494:pharmacology*; D009270:Naloxone / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology*; D058906:Purinergic P1 Receptor Agonists; D058915:Purinergic P1 Receptor Antagonists; D014665:Vasodilator Agents / Q000494:pharmacology
D009292:Narcotic Antagonists; D058906:Purinergic P1 Receptor Agonists; D058915:Purinergic P1 Receptor Antagonists; D014665:Vasodilator Agents; D019830:Adenosine-5'-(N-ethylcarboxamide); D009270:Naloxone; D009020:Morphine