Nicotinic acetylcholine receptors calcium effects

Fucile S (2004) Ca + permeability of nicotinic acetylcholine receptors. Cell Calcium 35 1-8 Gaddnas H, Pietila K, Ahtee L (2000) Effects of chronic oral nicotine treatment and its withdrawal on locomotor activity and brain monoamines in mice. Behav Brain Res 113 65-72 Geisler S, Derst C, Veh RW, Zahm DS (2007) Glutamatergic afferents of the ventral tegmental area in the rat. J Neurosci 27 5730-5743... 

Ridley DL, Pakkanen J, Wonnacott S (2002) Effects of chronic drug treatments on increases in intracellular calcium mediated by nicotinic acetylcholine receptors in SH-SY5Y cells, Br J Pharmacol 135 1051-1059... 

Ronde P, Nichols RA (1998) High calcium permeability of serotonin 5-HT3 receptors on presynaptic nerve terminals from rat striatum. J Neurochem 70 1094-1103 Rosenstein RE, Chuluyan HE, Cardinali DP (1990) Presynaptic effects of gamma-aminobutyric acid on norepinephrine release and uptake in rat pineal gland. J Neural Transm 82 131—40 Rousseau SJ, Jones IW, Pullar IA, Wonnacott S (2005) Presynaptic [alpha]7 and non-[alpha]7 nicotinic acetylcholine receptors modulate [3H]d-aspartate release from rat frontal cortex in vitro. Neuropharmacology 49 59... 

Histrionicotoxin, 342, and synthetic analog inhibition of ligand binding at sites associated with the sodium, potassium, and calcium channels in brain membrane preparations has been investigated [721]. The effects of 342 on the ion channel of central nervous system nicotinic acetylcholine receptors [722], and on post-tetanic potentiation of mouse and rat phrenic nerve diaphram preparations have been described [723]. 

All cell membranes contain transmembrane proteins that form ion channels. These ion channels are usually selectively permeable to particular ions. Some channels, such as GABA-gated ion channels, are permeable to Cl ions and are inhibitory in nature because they make the inside of the nerve or muscle cells more negative as the Cl ions enter. Some ion channels are permeable to the cations Na and K, and an example of this type is the nicotinic acetylcholine-gated channel. Nicotinic channels have an excitatory effect when they open because Na ions enter and K ions leave through these channels. The cell becomes more positive inside and depolarizes. If the cell is a muscle cell, calcium accumulates in the cytoplasm and it contracts. We have found that all over the surface of Ascaris muscle there are GABA receptors (Martin, 1980) as well as nicotinic acetylcholine channels (Martin, 1982 Robertson and Martin, 1993). 

Local anesthetics have poorly understood effects on inflammation at sites of injury, and these anti-inflammatory effects may contribute to improved pain control in some chronic pain syndromes. At the concentrations used in spinal anesthesia, local anesthetics can inhibit transmission via substance P (neurokinin-1), NMDA, and AMPA receptors in the secondary afferent neurons (Figure 26-1). These effects may contribute to the analgesia achieved by subarachnoid administration. Local anesthetics can also be shown to block a variety of other ion channels, including nicotinic acetylcholine channels in the spinal cord. However, there is no convincing evidence that this mechanism is important in the acute clinical effects of these drugs. High concentrations of local anesthetics in the subarachnoid space can interfere with intra-axonal transport and calcium homeostasis, contributing to potential spinal toxicity. 

Batrachotoxin has no effect on a calcium channel (18), or on potassium channels (795). However, batrachotoxin does appear to antagonize the increase in conductance elicited by nicotinic agonists in striated neuromuscular preparations (111) and adrenal glands (164, 165). The mechanism involved in inhibition of nicotinic receptor-controlled conductances by batrachotoxin remains unclear but actually might represent another site of action for the alkaloid. Batrachotoxin, however, has no effect on binding of a-bungarotoxin or histrionicotoxin to the acetylcholine receptor-channel... 

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