Homomers of alpha 8 and alpha 7 subunits of nicotinic receptors exhibit similar channel but contrasting binding site properties.
alpha 8 subunits of alpha-bungarotoxin-sensitive chick neuronal nicotinic acetylcholine receptors expressed in Xenopus oocytes from cRNA are shown to form homomeric, acetylcholine-gated, rapidly desensitizing, inwardly rectifying, Ca(2+)-permeable cation channels similar to those of alpha 7 homomers. alpha 8 forms oligomers of several sizes, of which < 14% are expressed on the oocyte surface, which is less efficient than for alpha 7 homomers. alpha 8 homomers are more sensitive to agonists but less sensitive to antagonists than are alpha 7 homomers, and some agonists for alpha 8 homomers are partial agonists or antagonists for alpha 7 homomers. The pharmacological properties of homomers of alpha 8 and alpha 7 subunits generally reflect those of native alpha 8 and alpha 7 receptors.
Gerzanich
V
V
Department of Neuroscience, University of Pennsylvania, Philadelphia 19104-6074.
Anand
R
R
Lindstrom
J
J
D000818:Animals; D001665:Binding Sites; D002038:Bungarotoxins / Q000378:metabolism / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002645:Chickens; D018118:Chloride Channels / Q000378:metabolism; D003001:Cloning, Molecular; D004594:Electrophysiology; D007473:Ion Channels / Q000378:metabolism*; D009538:Nicotine / Q000378:metabolism / Q000494:pharmacology; D009865:Oocytes / Q000378:metabolism; D010276:Parasympatholytics / Q000494:pharmacology; D010277:Parasympathomimetics / Q000494:pharmacology; D011978:Receptors, Nicotinic / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D014982:Xenopus laevis
D002038:Bungarotoxins; D018118:Chloride Channels; D007473:Ion Channels; D010276:Parasympatholytics; D010277:Parasympathomimetics; D011978:Receptors, Nicotinic; D009538:Nicotine; D002118:Calcium