Intravenous procaine as a probe of limbic system activity in psychiatric patients and normal controls

Evidence from animal and human studies suggests that procaine hydrochloride may selectively activate limbic system structures and suppress neocortical structures. We administered a series of intravenous bolus doses of procaine hydrochloride to 31 subjects (7 with affective disorders, 17 with borderline personality disorder, and 7 healthy normal volunteers). Dose-related cognitive and sensory distortions and illusions were observed; affective experiences ranged widely from euphoric to dysphoric. Topographic electroencephalogram (EEG) analysis indicated selective increases in fast activity (26-45 Hz) over the temporal lobes; the degree of increase in this activity correlated with degree of dysphoria experienced. Procaine was associated with increases in secretion of cortisol, adrenocorticotrophic hormone (ACTH), and prolactin, but not with growth hormone. These preliminary data are consistent with the possibility that procaine might serve as a clinically useful probe of psychosensory, affective, electrophysiological, and endocrine effects referable to the limbic system.