ABSTRACT Nicotine addiction is a persistent public health challenge, and smoking remains the leading cause of preventable disease and death in the United States. As of 2021, an estimated 46 million Americans smoke tobacco products or use e-cigarettes. This behavior imposes a financial burden of over $600 billion annually, including nearly $240 billion for direct medical care and almost $180 billion in lost productivity due to illness and premature death. While approximately 70% of those with nicotine dependence express a desire to quit, only one in ten successfully achieve nicotine abstinence for 12 months or more through Nicotine Replacement Therapy (NRT) and non-nicotine medications for smoking cessation. This low success rate highlights the urgent need for an innovative approach that goes beyond relieving nicotine cravings. Smoking and vaping are complex behaviors deeply ingrained through long-term conditioning. Quitting involves not only ending nicotine use but also navigating social settings, managing isolation from social networks, and coping with habitual oral fixations. To address this unmet need, we are developing a treatment based on the smoking cessation drug candidate, cytisine, to be self-administered in vape form using an e-cigarette or "vape pen." We propose that this approach would serve as an effective secondary line of therapy for individuals seeking e-cigarette and smoking cessation, particularly those who have experienced two or more unsuccessful attempts with existing NRT. It would allow them to engage in many smoking-related behaviors while simultaneously reducing their nicotine dependence. While the oral administration of cytisine for smoking cessation is well-established, our innovation lies in exploring the feasibility of delivering cytisine in vape form. The primary hypothesis of this Phase I grant is that delivering cytisine through Electronic Vape Administration (EVA) will sufficiently stabilize dopamine release in the brain, specifically the ventral striatum, thereby reducing nicotine self-administration in a mouse model of nicotine addiction. To test this hypothesis, we will, 1) determine the pharmacokinetics of cytisine by quantifying plasma cytisine concentrations after both oral and vape administration in a rodent model, 2) utilize a biosensor platform, dLight1.3b, to monitor core dopamine levels in vivo during nicotine self-administration, and 3) evaluate the potential abuse liability of EVA cytisine in e-Vape self-administration (EVSA) and assess the ability of EVA cytisine to reduce nicotine reinforcement using trained and nicotine-conditioned mice in a nicotine EVSA paradigm. This proposal provides the foundation for developing an e-cigarette vaping and smoking cessation product that offers a superior method of treatment tailored for patients who have not been successful with traditional NRT and oral administration treatments. Our team is uniquely positioned to achieve this aim. SpaceRx has extensive experienc...