Nicotine increases intracellular calcium in rat hippocampal neurons via voltage-gated calcium channels.
The effect of nicotinic receptor activation on intracellular calcium concentrations ([Ca2+]i) was quantitated in populations of cultured hippocampal neurons loaded with Fura-2. Nicotine (50 microM) and cytisine (50 microM) increased [Ca2+]i by 100%. This response was abolished in the presence of the nicotinic antagonist methyllycaconitine (MLA) whereas KCl-evoked increases in [Ca2+]i were insensitive to MLA. Glial cultures were unaffected by nicotine, although they did respond to glutamate with increased [Ca2+]i. In hippocampal neurons, responses to nicotinic agonists and KCl were dependent on the presence of extracellular Ca2+ and were similarly sensitive (85% inhibition) to CdCl2. These results are consistent with the presence of functional nicotinic receptors on hippocampal neurons. The receptors appear to elevate [Ca2+]i by promoting the influx of extracellular Ca2+ through voltage-gated calcium channels.
Barrantes
G E
GE
School of Biology and Biochemistry, University of Bath, UK.
Murphy
C T
CT
Westwick
J
J
Wonnacott
S
S
D000157:Aconitine / Q000031:analogs & derivatives / Q000494:pharmacology; D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D001392:Azocines; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000187:drug effects*; D002478:Cells, Cultured / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D016257:Fura-2; D006624:Hippocampus / Q000187:drug effects*; D008564:Membrane Potentials / Q000187:drug effects; D009538:Nicotine / Q000494:pharmacology*; D011807:Quinolizines; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors; D000093843:Quinolizidine Alkaloids
D000157:Aconitine; D000470:Alkaloids; D001392:Azocines; D002118:Calcium; D015220:Calcium Channels; D016257:Fura-2; D009538:Nicotine; D011807:Quinolizines; C054634:methyllycaconitine; C004712:cytisine; D000093843:Quinolizidine Alkaloids