Antinociceptive effect of intracerebroventricular injection of a tetrapeptide Asn-Ala-Gly-Ala in rats.
The antinociceptive effect of intracerebroventricular injection (icv) of Asn-Ala-Gly-Ala (NAGA), a partial sequence of beta-lipotropin, was studied in rats. The potassium iontophoresis-induced tail flick was used to measure the pain threshold. The antinociceptive effect of NAGA, which was dose-dependent (icv, 0.03-0.24 mumol/rat) and long-lasting (90 min), was reversed by naloxone (icv, 0.26 mg.kg-1) and inhibited by anti-MEK serum (titre: 1:5000, 5 microliters) or anti-LEK serum (titre: 1:5000, 5 microliters). NAGA-induced antinociception was scarcely affected by anti-beta-EP serum (titre: 1:30,000, 5 microliters) or anti-Dyn A1-13 serum (titre: 1:30,000, 5 microliters). It was suggested that the antinociceptive effect of NAGA may be associated with the release of met-enkephalin and leu-enkephalin in rat brain.
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Department of Biochemistry, Second Military Medical University, Shanghai, China.
Song
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Wei
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You
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Shi
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D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D004743:Enkephalin, Leucine / Q000276:immunology; D004744:Enkephalin, Methionine / Q000276:immunology; D007106:Immune Sera / Q000494:pharmacology; D007276:Injections, Intraventricular; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D009842:Oligopeptides / Q000494:pharmacology*; D017288:Pain Threshold / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley
D000700:Analgesics; D007106:Immune Sera; D009842:Oligopeptides; D009270:Naloxone; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; C038177:asparaginyl-alanyl-glycyl-alaninamide