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Acetylcholine Nicotine. Nicotinic acetylcholine receptors, or nAChRs, are receptor polypeptides that respond to the neurotransmitter acetylcholine. Nicotinic receptors also respond to drugs such as the agonist nicotine. They are found in the central and peripheral nervous system, muscle, and many other tissues of many organisms.
The alpha-7 nicotinic receptor, also known as the α7 receptor, is a type of nicotinic acetylcholine receptor implicated in long-term memory, consisting entirely of α7 subunits. [1] As with other nicotinic acetylcholine receptors, functional α7 receptors are pentameric [i.e., (α7) 5 stoichiometry ].
[2] [3] It is located in the autonomic ganglia [4] and adrenal medulla, [5] where activation yields post-and/or presynaptic excitation, [3] mainly by increased Na + and K + permeability. As with other nicotinic acetylcholine receptors, the α3β4 receptor is pentameric [(α3) m (β4) n where m + n = 5].
The α7 are not believed to have as much affinity for nicotine as the heteromeric receptor but instead they have shown more affinity for alpha bungarotoxin which is a nicotinic antagonist found in venom of some snakes. Targeting of α7 receptors is therefore thought to be useful in treatment of Alzheimer's disease and schizophrenia. [9] [15]
Nicotinic receptors are the primary mediator of the effects of nicotine. In myasthenia gravis, the receptor at the neuromuscular junction is targeted by antibodies, leading to muscle weakness. Muscarinic acetylcholine receptors can be blocked by the drugs atropine and scopolamine.
Nicotine effect on weight appears to result from nicotine's stimulation of α3β4 nAChR receptors located in the POMC neurons in the arcuate nucleus and subsequently the melanocortin system, especially the melanocortin-4 receptors on second-order neurons in the paraventricular nucleus of the hypothalamus, thus modulating feeding inhibition.
The proposed rule doesn't ban nicotine but lowers the amount allowed in cigarettes, cigarette tobacco, roll-your-own tobacco and most cigars to 0.7 milligrams per gram of tobacco − a smaller ...
The alpha-4 beta-2 nicotinic receptor, also known as the α4β2 receptor, is a type of nicotinic acetylcholine receptor implicated in learning, [1] consisting of α4 and β2 subunits. [2] It is located in the brain , where activation yields post- and presynaptic excitation , [ 2 ] mainly by increased Na + and K + permeability.