The Effect of Dynorphin on Analgesia and Respiration

Year 1982, Volume: 35 Issue: 2, 317 - 322, 01.07.1982

Cankat Tulunay

Abstract

Dynorphin is a newly discovered opioid peptide with up to 700 times stronger effect than morphine in certain isolated tissue preparations. However, in whole animal studies, it does not show appreciable analgesic or respiratory depressant activity. When co-administered with morphine, it antagonizes morphine-induced analgesia while potentiating its respiratory depressant effects in naive mice. In morphine-dependent mice, dynorphin enhances the analgesic effect of morphine and antagonizes its respiratory depression. Ethylketocyclazocine (ECZ), a kappa receptor agonist, induces strong analgesia and respiratory depression when administered alone, and antagonizes morphine's effects in both naive and morphine-dependent animals when co-administered. These results suggest that different opioid effects are mediated via different receptor types, and dynorphin modulates these effects differently in naive and tolerant subjects.

Keywords

dynorphin , morphine , analgesia , respiration , opioid peptide , tolerance , naloxone , kappa agonist

Ethical Statement

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Supporting Institution

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Thanks

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Dynorphin'in Analjezi ve Solunum Üzerine Etkisi

Abstract

Dynorphin yeni keşfedilmiş bir opioid peptid olup bazı izole doku preparatlarında morfinden 700 kat daha kuvvetli etkiye sahiptir. Ancak tam hayvanda analjezik ve solunumu deprese edici etkisi gözlenmemiştir. Morfinle birlikte verildiğinde, normal hayvanlarda morfinin analjezik etkisini antagonize ederken, solunumu baskılayıcı etkisini potansiyalize etmektedir. Morfine bağımlı hayvanlarda ise morfinin analjezik etkisini artırmakta, solunumu baskılayıcı etkisini ise azaltmaktadır. Kappa reseptör agonisti olan etilketosiklozosin (ECZ) tek başına verildiğinde kuvvetli analjezik etki oluşturmakta ve solunumu deprese etmektedir. Morfinle birlikte verildiğinde ise, düşük dozlarda hem normal hem de morfin bağımlı hayvanlarda morfinin etkilerini antagonize etmektedir. Bu sonuçlar, opioidlerin farklı farmakolojik etkilerinin farklı reseptörler aracılığıyla oluştuğunu ve dynorphin'in bu etkileri normal ve toleran hayvanlarda farklı şekilde modüle ettiğini göstermektedir.

Keywords

dynorphin , morfin , analjezi , solunum , opioid peptid , tolerans , nalokson , kappa agonist

Project Number

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References

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