• Archives of Pharmacal Research
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• v.16 no.2
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• pp.83-88
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• 1993

opioid pure agonists, morphine, meperidine and methadone, were used to investigate the effect on the opioid receptor of fron sciatic nerve fibers using sucrose gap apparatus. When applied extracellularly by perfusion, morphine, methadone and meperidine significantly depressed the amplitude of the action potential in frog sciatic nerve fibers as a dose-dependent $(10^{-10}\;M-10^{-2}\;M)$ manner. The depression with morphine or methadone was partially antagonized by the simultaueous treatment with a lower $(10^{-10}\;M-10^{-8}\;M)$ concentration of naloxone, but that of meperidine was not blocked. When the three opioid agonists were applied intracellularly by placing it in a compartment with a cut end of the sciatic nerve fibers, all of themn depressed the amplitude of the action potentials by similar potency, and these reductions significantly blocked by pretreatment of lower concentration $(10^{-10}\;M-10^{-8}M)$ of naloxone. These results support the previous findings by other workers that the stereospecific opioid receptors of this preparation are located on or near the intracellular opening of the sodium channels which are sensitive to naloxone.

• The Korean Journal of Pharmacology
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• v.25 no.1
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• pp.23-30
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• 1989

Buprenorphine, one of the mixed agonist-antagonist opioid drugs was used to inverstigate the opioid receptor on frog sciatic nerve A fibers. Action potentials were recorded for 4 hrs by a sucrose gap apparatus which were separated by four rubber membranes. To examine the one of the mechanism of action of buprenorphine, meperidine or naloxone was added after or before the treatment of buprenorphine. The results of this experiment were as follows: 1. Buprenorphine suppressed significantly the compound action potentials of frog sciatic nerve, and the maximal effects were shown both at $10^{-4}\;M$ and at $10^{-8}\;M$. 2. The dose-response relationship of buprenorphine on the depressant effect in frog sciatic nerve was biphasic and inverted U-shaped. 3. Buprenorphine blocked the effect of Meperidine $(10^{-3}\;M)$ on this preparation. 4. The depressant effcct of Buprenorphine on frog sciatic nerve was blocked by $10^{-8}\;M$ naloxone. From the above results, buprenorphine acts as one of agoinist-antagonistic effect on frog sciatic nerve, and the opioid receptor on this preparation is located on or near the intracellular opening of the sodium channels, which are sensitive to naloxone.