Anxiogenic effects of noreleagnine, a water soluble beta-carboline in rats.

We tested noreleagnine, a beta-carboline which unlike other beta-carbolines remains in aqueous solution at physiological pH, as well as chlordiazepoxide, a traditional benzodiazepine, and their interaction with the benzodiazepine receptor antagonist R0 15-1788 in a modified approach schedule with two levels of conflict. Noreleagnine displayed pro-conflict activity characteristic of beta-carbolines and chlordiazepoxide elicited an anti-conflict effect, both of which were blocked by pretreatment with R0 15-1788. We believe this to be the first clear demonstration that noreleagnine has an anxiogenic effect and that this effect is mediated by its action on benzodiazepine receptors.