Binding, antagonist/receptor effectiveness

Rimcazole (BW 234U) (496) is a novel anti-pyretic, neuroleptic agent. It was found to be a specific competitive antagonist of a-sites in the brain. It reverses psychotic conditions induced in humans by phencyclidine and/or a-opiod antagonists, probably by binding to receptors in the brain (459-461). Rimcazole has an indirect effect on dopamine neurons with relative selectivity for AlO dopamine cells (462). 

A new H3 antagonist AQ 145 (N-l-adamantyi-N N [l,5-(3-4,(5)-lH imidazolyl)-petanediyl]formamidine dihydrochloride) was synthesized by Green Cross Pharmac. Co, Osaka, Japan. AQ 145 has 5-fold higher affinity to H3 receptors than thioperamide in in vitro binding assay. The effect of this compound on electrically-induced convulsions in mice was examined as similarly as described above. The durations of tonic, clonic and convulsive come phases were significantly decreased by i.p. administration of 30 mg/kg dose [6]. 

Naloxone is a pure competitive antagonist at all opioid receptors, notably the p- and K- receptors it has no agonist activity. Naloxone antagonises both agonist and partial agonist opioids (although it may not be sufficient to reverse the effects of buprenorphine in overdose, so tenaciously does the latter drug bind to receptors). It induces an acute withdrawal syndrome in opioid-dependent subjects. 

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