Effects of beta-adrenergic blocking agents on specific binding of [3H]D-Ala2-Met5-enkephalinamide and [3H]naloxone.

H. Takayama, N. Ogawa, M. Asanuma, H. Hirata, T. Ogura, Z. Ota

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


To gain further insight into the central nervous system (CNS)-action of beta-adrenergic blocking agents (beta-blockers), we examined the effects of various kinds of beta-blockers on opioid receptors (Op-Rs) using radiolabeled receptor assay (RRA). We demonstrated that beta-blockers are competitively bound to Op-Rs in the CNS. Sodium index of beta-blockers in [3H]naloxone binding study indicated that beta-blockers had the mixed agonist-antagonist activity of opiates. The relative potency of beta-blockers in opioid RRA was negatively correlated with their membrane stabilizing activity. Neither beta-blocking activity nor intrinsic sympathomimetic activity was correlated with IC50 values of beta-blockers in opioid RRA. While it is widely accepted that beta-blockers have a tranquilizing activity, a part of the tranquilizing action of beta-blockers may be mediated through Op-Rs in the CNS. Although beta-blockers may have effects on their own receptors (beta-receptors) in the CNS, the more precise mechanisms of central action of these drugs must be further investigated.

Original languageEnglish
Pages (from-to)295-299
Number of pages5
JournalActa medica Okayama
Issue number5
Publication statusPublished - Oct 1991

ASJC Scopus subject areas

  • General Biochemistry,Genetics and Molecular Biology


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