Behavioral alterations induced by an escalating dose-binge pattern of cocaine administration

Stimulant-induced psychosis and addiction are most commonly associated with a pattern of repeated high dose 'binge' exposures, preceded by progressively escalating doses (ED). We have recently reported that an ED/multiple binge treatment with amphetamine or methamphetamine results in a unique behavioral profile, characterized by a differential change in the relative expression of locomotion and stereotypy and the emergence of a bursting pattern of ambulation. To examine the generality of this behavioral profile, a similar regimen (ED, 2-15 mg/kg; binges, 15 mg/kg x 5 hourly injections x 15 days) was used to characterize the response to cocaine. Our results show that the primary characteristics of the behavioral profile previously found with the amphetamines were also apparent with cocaine. That is, the locomotor response was significantly greater, and was characterized by a bursting pattern. These observations lend further support to the notion that the progressive behavioral changes and the underlying neurochemical alterations produced by this treatment may be implicated in the addiction and psychosis which is associated with high dose stimulant abuse.