lobeline

Lobeline is an alkaloid found in "Indian tobacco" (Lobelia inflata), "Devil's tobacco" (Lobelia tupa), "cardinal flower" (Lobelia cardinalis), "great lobelia" (Lobelia siphilitica), and Hippobroma longiflora. Additionally, it is also found in Lobelia Chinensis. In its pure form, it is a white amorphous powder which is freely soluble in water. Lobeline has been sold, in tablet form, for use as a smoking cessation aid, and may have application in the treatment of other drug addictions such as addiction to amphetamines, cocaine, or alcohol. Lobeline has multiple mechanisms of action, acting as a VMAT2 ligand, which stimulates dopamine release to a moderate extent when administered alone, but reduces the dopamine release caused by methamphetamine. It also inhibits the reuptake of dopamine and serotonin and acts as a mixed agonist-antagonist at nicotinic acetylcholine receptors to which it binds at the subunit interfaces of the extracellular domain. It is also an antagonist at μ-opioid receptors. It seems to be a P-glycoprotein inhibitor, according to at least one study. It has been hypothesized that P-glycoprotein inhibition reduces chemotherapeutic resistance in cancer, presumably affecting any substrates of P-gp. — NCATS