Nicotinic receptor mediated stimulation of NO-generation in neurons of rat thoracic dorsal root ganglia.
The contribution of nicotinic acetylcholine receptors (nAChRs) to stimulation of NO-production was investigated in isolated rat dorsal root ganglion (DRG) neurons utilizing an NO-sensitive fluorescent indicator 4,5-diaminofluorescein-diacetate (DAF-2DA) and appropriate channel blockers. RT-PCR and immunohistochemical analysis of NOS isoforms in cultured neurons revealed the expression of eNOS in the vast majority of neurons, nNOS in about 5-10%, and iNOS only exceptionally. Application of nicotine resulted in an abrupt increase in DAF-2T fluorescence in 65% of neuronal cell bodies that was fully sensitive to the general nAChR antagonist mecamylamine. Methyllycaconitine reduced the number of nicotine-sensitive neurons and the extent of NO-generation. Thus, alpha7- and/or alpha9/10-nAChRs are required for nicotine-induced NO-production in a subpopulation of DRG neurons, and appear to be partially involved in the remaining, larger subpopulation.
Papadopolou
S
S
Institute for Anatomy and Cell Biology, Justus-Liebig-University Giessen, Aulweg 123, 35385 Giessen, Germany.
Hartmann
P
P
Lips
K S
KS
Kummer
W
W
Haberberger
R V
RV
D000818:Animals; D002478:Cells, Cultured; D005260:Female; D019793:Fluorescein; D005727:Ganglia, Spinal / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D009475:Neurons, Afferent / Q000187:drug effects / Q000201:enzymology*; D009538:Nicotine / Q000494:pharmacology; D018733:Nicotinic Antagonists / Q000494:pharmacology; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011978:Receptors, Nicotinic / Q000187:drug effects / Q000378:metabolism*; D064569:alpha7 Nicotinic Acetylcholine Receptor
C414689:4,5-diaminofluorescein diacetate; C579165:Chrna7 protein, rat; D018733:Nicotinic Antagonists; D012333:RNA, Messenger; D011978:Receptors, Nicotinic; D064569:alpha7 Nicotinic Acetylcholine Receptor; C443079:nAChR alpha9; D009569:Nitric Oxide; D009538:Nicotine; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496322:Nos1 protein, rat; C496318:Nos2 protein, rat; C496316:Nos3 protein, rat; D019793:Fluorescein