Putrescine is a polyamine with multiple roles in cellular metabolism. It is also a minor precursor of the inhibitory neurotransmitter, gamma-aminobutyric acid (GABA). Conversion of systemically administered putrescine to GABA in rat neural tissues has been reported. In this thesis, three experiments were conducted to characterize changes in rat behavior after putrescine administration, and determine if any effects resembled known GABAergic behaviors. Experiments l and 2 investigated the behavioral consequences of oral and intraperitoneal putrescine treatment. Male adult rats were given either saline or putrescine doses and tested with seven procedures which evaluated motor behavior, sensory reactivity, body temperature, and other behaviors. Results showed that putrescine-treated subjects exhibited significant changes in behavior compared to saline controls, and that certain effects resembled behaviors related to the function of GABA and/or other neurochemicals. Experiment 3 investigated the modifying effects of putrescine treatment on behavior induced by a dopamine agonist, apomorphine, and were compared to effects produced by a GABA agonist, muscimol. Male adult rats were given either saline, putrescine, or muscimol, and later treated with saline or apomorphine. Locomotor and specific activities were time sampled for 45 minutes. Results indicated that putrescine and muscimol had similar interactions with apomorphine in modifying sniffing stereotypies. From the behavioral evidence obtained in this thesis, it was suggested that systemic putrescine administration may indirectly influence behavior in the rat via GABAergic mechanisms. The results were interpreted as preliminary support for a significant neuropharamacological role of putrescine in the mammalian central nervous system. / Master of Science