Behavioral and neurochemical effects of deprenyl and beta-phenylethylamine in Wistar rats

The effects of 1-deprenyl (1-16 mg kg-1, 3.5 hr) on brain levels of endogenous beta-phenylethylamine were assessed in animals under three conditions: (1) experience of lateral hypothalamic self-stimulation; (2) electrode implantation but no self-stimulation experience; (3) no surgical intervention. The increase in striatal levels of beta-phenylethylamine with 1-deprenyl treatment was attenuated in the self-stimulation condition relative to conditions (2) and (3). This differential effect of 1-deprenyl was not observed at the level of the hypothalamus. Administration of 1-deprenyl did not affect self-stimulation behavior. Equivalent analysis of beta-phenylethylamine levels was carried out using animals injected with beta-phenylethylamine (0.5-4 mg kg-1, 0.5 hr 1P and 1-deprenyl (4 mg kg-1, 3.5 hr sc). Injected beta-phenylethylamine with deprenyl pretreatment increased self-stimulation rates; concomitant striatal levels of approximately 190 ng g-1 of beta-phenylethylamine were observed and were associated with increased brainstem 5-HIAA but no change in striatal HVA, indicating possible involvement of 5-HT in this response to beta-phenylethylamine. It is proposed that experience of electrical hypothalamic stimulation may alter endogenous striatal beta-phenylethylamine metabolism, possibly via an alteration of mechanisms governing synthesis and/or catabolism.