Effects of PCPA on the consumption of alcohol, water and other solutions

The influence of para-chlorophenylalanine (PCPA) on the preference for alcohol, saccharin, glucose, and sodium chloride solutions and on water intake was studied in rats. Ten daily intragastric doses of 100 mg/kg PCPA were found to reduce alcohol preference both during and after PCPA treatment. Administration of daily 20 mg/kg IP doses of 5-hydroxtryptophan (5-HTP), plus a peripheral decarboxylase inhibitor, failed to reverse the PCPA-induced suppression in the post-PCPA test. Alcohol preference was not reduced below baseline following PCPA if this drug was administered between preference tests rater than coincident with alcohol drinking. Preference for saccharin, glucose, and sodium chloride solutions were all affected by PCPA. Large increases in water intake were produced by 50, 100, or 200 mg/kg PCPA given orally for 10 days. These experiments suggest that alcohol preference, in studies where PCPA treatment and alcohol drinking occur concurrently, may be considerably influenced by learned aversions to alcohol. Also, PCPA may, under some circumstances, produce an increased consumption of water by rats.