Nicotinici

Nicotinici is an Italian term used to describe matters related to nicotine or to nicotinic acetylcholine receptors (nAChRs). In pharmacology and neuroscience, the focus is on how nicotine interacts with these receptors and how their distribution and function influence physiology and behavior.

Nicotinic acetylcholine receptors are pentameric ligand-gated ion channels found in the central nervous system and at the neuromuscular junction. They are assembled from a variety of subunits, including alpha (α) and beta (β) types, with subunit composition determining receptor properties. Neuronal nAChRs commonly include subtypes such as α4β2 and the homomeric α7 receptor, while muscular receptors at the neuromuscular junction typically involve different subunit combinations, such as α1 with other partners. Receptor activation opens cation channels, allowing Na+ and Ca2+ influx, which depolarizes cells and modulates neurotransmitter release.

Nicotine, the primary psychoactive alkaloid in tobacco, acts as an agonist at many nAChR subtypes. In the brain, activation of nAChRs modulates attention, arousal, and reward pathways, notably influencing dopamine release in mesolimbic circuits and contributing to nicotine dependence. Chronic exposure can lead to receptor upregulation in some subtypes and to receptor desensitization, processes associated with tolerance and withdrawal.

Therapeutically, nicotinic agents are used in smoking cessation (nicotine replacement therapies and partial agonists such as varenicline) and are investigated for cognitive disorders and inflammatory conditions. Research continues to explore subtype-selective ligands to target specific neural circuits while minimizing adverse effects.

Overall, nicotinici encompasses the study of nicotine’s pharmacology, the diverse nAChR subtypes, and their roles in physiology, addiction, and potential therapeutic applications.