Rationale: A few recent studies suggest that brain histamine levels and signaling via H(3) receptors play an important role in modulation of alcohol stimulation and reward in rodents.
Objective: The present study characterized the effects of a novel, selective, and brain penetrant H(3) receptor antagonist (JNJ-39220675) on the reinforcing effects of alcohol in rats.
Methods: The effect of JNJ-39220675 on alcohol intake and alcohol relapse-like behavior was evaluated in selectively bred alcohol-preferring (P) rats using the standard two-bottle choice method. The compound was also tested on operant alcohol self administration in non-dependent rats and on alcohol-induced ataxia using the rotarod apparatus. In addition, alcohol-induced dopamine release in the nucleus accumbens was tested in freely moving rats.
Results: Subcutaneous administration of the selective H(3) receptor antagonist dose-dependently reduced both alcohol intake and preference in alcohol-preferring rats. JNJ-39220675 also reduced alcohol preference in the same strain of rats following a 3-day alcohol deprivation. The compound significantly and dose-dependently reduced alcohol self-administration without changing saccharin self-administration in alcohol non-dependent rats. Furthermore, the compound did not change the ataxic effects of alcohol, alcohol elimination rate, nor alcohol-induced dopamine release in nucleus accumbens.
Conclusions: These results indicate that blockade of H(3) receptor should be considered as a new attractive mechanism for the treatment of alcoholism.