Single channel properties of neuronal nicotinic ACh receptors in stratum radiatum interneurons of rat hippocampal slices.
The single channel properties of neuronal nicotinic ACh receptors (nAChRs) were investigated in outside-out patches from CA1 stratum radiatum interneurons from thin slices of rat hippocampus. The application of ACh (10 microM to 1 mM) induced the opening of observable single channel currents with two distinct current levels, which corresponded to conductance levels of 38 +/- 3 and 62 +/- 2 pS. The 38 pS channel was observed in 10 % (n = 260) of patches, whereas the 62 pS channel was observed in 4 % of patches; these two channel types were most often observed independently. The alpha7-selective nAChR antagonist methyllycaconitine (MLA; 50 nM) reduced the open probability of the 38 pS channel by 73 %. In contrast, the 62 pS channel was unaffected by MLA, but instead was blocked by dihydro-beta-erythroidine (DHbetaE; 10 microM), a broad spectrum nAChR antagonist. These data suggest that rat hippocampal CA1 stratum radiatum interneurons in the slice possess at least two different types of functional nAChRs, an alpha7-containing subtype with a single channel conductance of 38 pS, and a non-alpha7 subtype with a single channel conductance of 62 pS.
Shao
Z
Z
Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, National Institutes of Health, PO Box 12233, Research Triangle Park, NC 27709, USA.
Yakel
J L
JL
D000109:Acetylcholine / Q000494:pharmacology; D000157:Aconitine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D004079:Dihydro-beta-Erythroidine / Q000494:pharmacology; D004594:Electrophysiology; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D066298:In Vitro Techniques; D007395:Interneurons / Q000378:metabolism; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism; D008297:Male; D018722:Nicotinic Agonists / Q000494:pharmacology; D018733:Nicotinic Antagonists / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar; D011978:Receptors, Nicotinic / Q000187:drug effects / Q000378:metabolism*
D007473:Ion Channels; D018722:Nicotinic Agonists; D018733:Nicotinic Antagonists; D011978:Receptors, Nicotinic; C054634:methyllycaconitine; D004079:Dihydro-beta-Erythroidine; D000109:Acetylcholine; D000157:Aconitine