Nicotinic receptors mechanisms

Sacco KA, Termine A, Seyal A, Dudas MM, Vessicchio JC, et al. 2005. Effects of cigarette smoking on spatial working memory and attentional deficits in schizophrenia Involvement of nicotinic receptor mechanisms. Arch of Gen Psychiatry 62 649-659. 

George TP, Termine A, Sacco KA, Allen TM, Reutenauer E, et al. 2006. A preliminary study of the effects of cigarette smoking on prepulse inhibition in schizophrenia Involvement of nicotinic receptor mechanisms. Schizophr Res 87 307-315. 

Lobeline. The alkaloid lobehne, whose mechanism of action in unclear but that appears to have dopamine reuptake blockade and nicotinic receptor antagonist properties (Dwoskin and Crooks 2002), was evaluated in a double-bhnd, randomized, placebo-controUed, multicenter trial involving 180 ciga-... 

With endplate nicotinic receptors it has been found that, as well as activating the receptor, acetylcholine (ACh) blocks the ion channel. A possible mechanism to describe this situation (assuming for simplicity only a single agonist binding is required to activate the receptor) might therefore be ... 

Given the role of acetylcholine receptors in analgesic circuits, it is not surprising that a number of plants with cholinergic mechanisms have analgesic effects. The RVM has muscarinic and nicotinic receptors (Cortes and Palacios 1986 London et al. 1985). The PAG has nicotinic receptors as well (Segal et al. 1978). 

Zarrindast MR, Pazouki M, Nassiri-Rad S. (1997). Involvement of cholinergic and opioid receptor mechanisms in nicotine-induced antinociception. Pharmacoi Toxicoi. 81(5) 209-13. 

Ellers H, Schaeffer E, Bidder PE, Forsayeth JR (1997) Functional deactivation of the major neuronal nicotinic receptor caused by nicotine and a protein kinase C-dependent mechanism. Mol Pharmacol 52 1105-1112... 

Vallejo YE, Buisson B, Bertrand D, Green WN (2005) Chronic nicotine exposure upregulates nicotinic receptors by a novel mechanism. J Neurosci 25 5563-5572 Vemino S, Amador M, Luetje CW, Patrick J, Dani JA (1992) Calcium modulation and high calcium permeability of neuronal nicotinic acetylcholine receptors. Neuron 8 127-134 Vizi ES, Lendvai B (1999) Modulatory role of presynaptic nicotinic receptors in synaptic and non-synaptic chemical communication in the central nervous system. Brain Res Brain Res Rev 30 219-235... 

Ion channels (center). These receptors contain ligand-gated ion channels. Binding of the signaling substance opens the channels for ions such as Na, Ca, and Cl . This mechanism is mainly used by neurotransmitters such as acetylcholine (nicotinic receptor see p.224) and GABA (A receptor see p.354). 

Several inhibitors of AChE have been developed for use in treating Alzheimer s disease, which requires that the drugs readily enter the CNS. These inhibitors are structurally unrelated and vary in their mechanism of inhibition, although all are reversible inhibitors. Tacrine (Cognex) is a monoamine acridine. Donepezil (Aricept) is a piperidine derivative that is a relatively specific inhibitor of AChE in the brain, with little effect on pseudo-ChE in the periphery. Galanthamine (Reminyl) is a tertiary alkaloid and phenanthrene derivative extracted from daffodil bulbs that is a reversible competitive inhibitor of AChE it also acts on nicotinic receptors. 

It has been suggested that abnormalities in attention-deficit/hyperactivity disorder in children and adults may be similar to those seen in early stages of PD (McCracken 1991). Of interest is that nicotinic mechanisms interact closely with dopamine systems (Kirch et al. 1988) and that nicotinic receptors may serve to regulate dopamine release (Clarke and Pert 1985 Rapier et al. 1990) in striatal and mesolimbic pathways. Nicotine is now being tried as an experimental treatment for attention-deficit/hyperactivity disorder in adults (Levin et al. 1995). 

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