Effects of the putative antagonist @entity33738 on the behavioral pharmacological actions of @entity15221 in XXXX .

@entity1 @entity19 @entity15221 @entity33738 @entity2933 @entity35 @entity734
RATIONALE: @entity15221 ( @entity2933 ) is an endogenous chemical found in the @entity1 brain that when administered systemically readily crosses the blood-brain barrier and produces behavioral effects. Some previously reported observations, including reports of specific antagonism by @entity33738 ( @entity33738 ), support the hypothesis that @entity2933 is a neurotransmitter with its own receptor system. In addition to its uncertain physiological role, the recent interest in @entity2933 has been engendered by its illicit use and abuse. OBJECTIVES: To further characterize the behavioral effects of @entity2933 and to evaluate @entity33738 for its potential antagonistic effects. METHODS: Following the administration of @entity2933 alone and in combination with @entity33738 , @entity19 were tested in a Functional Observational Battery (FOB) and for their effects on locomotor activity and on schedule-maintained behavior. Additionally, spontaneous and @entity33738 -precipitated withdrawal in @entity35 chronically treated with @entity2933 was examined. RESULTS: In the FOB, @entity2933 generally produced depressant-like effects that were generally not reversed by @entity33738 . @entity2933 also dose dependently reduced locomotor activity and rates of operant behavior, which were generally not reversed by co-administrations with @entity33738 . Neither spontaneous nor @entity33738 -precipitated signs of physical dependence were observed following chronic @entity2933 administration. CONCLUSION: @entity2933 dose dependently produced depressant-like effects on learned and unlearned behavior. The putative @entity2933 antagonist @entity33738 failed to convincingly antagonize these effects. @entity734 was not evident following spontaneous withdrawal or @entity33738 challenge. Taken together, these results suggest that @entity33738 's ability to antagonize @entity2933 's effects may be very limited.
