Behavioral Effects of Drugs (Inpatient): 42 (Cocaine and Zolmitriptan)

Cocaine potently inhibits the reuptake of serotonin (5-HT). Increased synaptic 5-HT resulting from this reuptake inhibition activates multiple 5-HT receptor subtypes. Some of these receptor subtypes have been implicated in the abuse-related effects of cocaine, including its primary reinforcing effects (i.e., cocaine taking behavior). 5-HT1b receptors, which are autoreceptors on 5-HT nerve endings that regulate 5-HT release and heteroreceptors that also mediate other neurotransmitter release, play a particularly important role in cocaine effects, likely because they are highly expressed in the mesocorticolimbic system. The 5-HT1b system displays profound dysregulation during both active cocaine use and abstinence. Initial preclinical research showed that selective 5-HT1b agonists enhanced the reinforcing and locomotor effects of cocaine during ongoing cocaine administration, but subsequent research showed that these agents robustly attenuated reinstatement of cocaine- and cue-primed cocaine seeking behavior. These findings have been replicated in rigorously conducted studies using multiple schedules of reinforcement and negative sucrose reinforcement controls across laboratories. Notably, though, these preclinical studies used compounds not approved for use in humans, hindering translation. Recently published data show that zolmitriptan, a commercially available selective 5-HT1b agonist migraine medication, also selectively attenuates the reinforcing and other abuse-related effects of cocaine, regardless of stage of use (i.e., ongoing or extinguished cocaine self-administration).

Although a robust preclinical literature supports the premise that 5-HT1b activation reduces a number of cocaine-associated behaviors (e.g., self-administration, cocaine seeking), this area remains unstudied in humans. The overarching goal of this project is to advance these promising preclinical findings, specifically those with zolmitriptan, to a clinical population, thereby demonstrating that the 5-HT1b system plays a key role in the effects of cocaine in humans