Klaus Minck

Substrate Analogue Renin Inhibitors Containing Replacements of Histidine in P2 or Isosteres of the Amide Bond Between P3 and P2 Sites

The search for orally active renin inhibitors as therapeutic agents continues to represent a challenging target for medicinal chemists.1 Analogues of the angiotensinogen region flanking the bond split by renin have turned out to be very potent and specific inhibitors of renin. However, the high affinity of these angiotensinogen analogues for human renin is often associated with fast hydrolysis between P3 and P2 sites by the intestinal serine protease chymotrypsin.2

Antagonism of the anxiolytic action of diazepam and chlordiazepoxide by the novel imidazopyridines, EMD 39593 and EMD 41717

The imidazopyridines EMD 35993 and EMD 41717 antagonized the anticonflict actions of diazepam and chlordiazepoxide in rodent models which are predictive for anxiolytic action in man. In contrast to other described benzodiazepine antagonists, these compounds did not antagonize either the anticonvulsant or muscle relaxant properties of either benzodiazepine. Both EMD 39593 and EMD 41717 competitively inhibit the binding of [3H]diazepam to brain membranes, but do not exhibit regional differences in potency. These observations suggest that both EMD 39593 and EMD 41717 display some selectivity in antagonizing the anxiolytic properties of benzodiazepines, and as such may be useful tools in identifying neuronal substrates of anxiety.