Nifene
Nifene is a high affinity, selective nicotinic α4β2* receptor partial agonist used in medical research for nicotinic acetylcholine receptors, usually in the form of nifene (18F) as a positron emission tomography (PET) radiotracer. Nifene has been used to assess the efficacy of acetylcholinesterase inhibitors in animal models, because the neurotransmitter acetylcholine competes with the binding of nifene at the nicotinic receptor site.