Date of Award


Degree Name

Master of Arts



First Advisor

Dr. Frederick P. Gault

Second Advisor

Dr. Arthur Snapper

Third Advisor

Dr. David Lyon

Access Setting

Masters Thesis-Open Access


The literature concerning the effects of d, l-parachlorophenylalanine (PCPA) upon shock-induced aggression (SIA) is reviewed and found to be inconsistent. PCPA, a known serotonin depletor, has behavioral effects in a variety of other procedures which collectively suggest that PCPA should produce SIA enhancement. The present study was designed to analyze PCPA (300 mg/kg) effects upon SIA in rats restrained spatially close to an inanimate target and panel operandum. The results showed marked increases in both aggressive biting and panel pressing for several days following each PCPA treatment for each subject tested. These data were interpreted to indicate that serotonin depletion by PCPA does indeed enhance SIA but that this effect is not selective for aggression. Several potential controlling variables are suggested to account for previous failures to obtain SIA increases after PCPA. Principal among these are the methodological complications inherent in the "social" assay procedures employed in all previous PCPA-SIA studies. It is concluded that earlier accounts which emphasized differing neurochemical mediators across aggression assays may have been premature. Rather, procedural variables may be the critical determinants of variation in reported PCPA-aggression effects across studies.