Intracellular Ca2+ dynamics of hippocampal interneurons following nicotinic acetylcholine receptor activation.
Ca2+ permeability of central nicotinic acetylcholine receptors (nAChRs), especially the alpha7 subunits, are exceptionally high and this important feature provide a special functional importance for these receptors at the system level. Although studies at the cellular level extensively characterized the molecular properties of Ca2+ influx following nAChR activation, much less is known about the time-related Ca2+ dynamics during nicotine administration in integration units of neurons. Such studies are of particular relevance to understanding in situ nonsynaptic actions of nicotine. Puff ejection of drugs produce a rapid drug delivery and elimination from the cell surface allowing the activation of extrasynaptic receptors within desensitization time-frame. In this report we provide evidence that rapid nicotine application is able to produce irregular Ca2+ transients in the dendrites of stratum radiatum interneurons in the hippocampal CA1 region. Potential components and mechanisms of nAChR-mediated Ca2+ influx are discussed in details to demonstrate the unique feature of activation of nAChRs involved in nonsynaptic function in interneurons as compared to other types of nicotinic activity.
Szabo
Szilard I
SI
Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1083 Budapest, Szigony u. 43, Hungary.
Zelles
Tibor
T
Lendvai
Balazs
B
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism*; D007395:Interneurons / Q000378:metabolism*; D009538:Nicotine / Q000008:administration & dosage; D051381:Rats; D017208:Rats, Wistar; D011978:Receptors, Nicotinic / Q000187:drug effects*
D011978:Receptors, Nicotinic; D009538:Nicotine; D002118:Calcium