Drugs of abuse mediate their rewarding, stimulant, conditioned and motivational effects by activating dopaminergic and GABAergic neurons in the ventral tegmental area that project to cortical and limbic regions. Repeated use of opiates and other drugs of abuse results in adaptations in these motivational systems in addicted individuals. Our research paradigms in addiction examine the role of gamma-aminobutyric acid GABA-B receptors in the ventral tegmental area of the midbrain. We utilize state-of-the-art methods in behavioral neuroscience, neuroanatomy, and neurochemistry to study these neural systems in addiction. We are also involved in translational research that examines the effects of pharmacological agents in human addiction. We test the effects of pharmacological agents on nicotine craving and withdrawal in smokers and in smokers with schizophrenia. Our translational work uses "bench to bedside" approaches in examining the neurobiological mechanisms of addiction and related neuropharmacological treatment approaches to this chronic relapsing disorder.