Involvement of different opioid receptor subtypes in electric shock-induced analgesia and motor suppression in the rat

Toshitaka Nabeshima, Kiyoshi Matsuno, Tsutomu Kameyama

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12 Citations (Scopus)

Abstract

We have investigated the correlation of electric shock-induced behavioral changes and functional alterations of endogenous opioid receptor subtypes. The degree of electric shock-induced behavioral changes, such as analgesia and motor suppression, was dependent on the duration of and time after electric shock application. The electric shock-induced behavioral changes were completely antagonized by naloxone. The apparent development of tolerance to both behavioral effects as a result of successive daily electric shock was different: Tolerance to electric shock-induced analgesia developed after 2 days' successive electric shock application, while tolerance to motor suppression was not observed even after 7 days' successive electric shock application. There was a decrease of [3H][D-Ala2, Met5]enkephalinamide ([3H]DAMEA, δ agonist) binding and an increase of [3H]naloxone (μ antagonist) binding when potent electric shock-induced analgesia developed. On the other hand, the binding of [3H]DAMEA and [3H]ethylketocyclazocine (κ agonist) was significantly changed when locomotion was suppressed. These results suggest strongly that different opioid systems may participate in electric shock-induced analgesia and motor suppression: electric shock-induced analgesia and motor suppression may be mediated by μ/δ and κ/δ receptors, respectively.

Original languageEnglish
Pages (from-to)197-207
Number of pages11
JournalEuropean Journal of Pharmacology
Volume114
Issue number2
DOIs
Publication statusPublished - 15-08-1985
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Pharmacology

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