TY - JOUR
T1 - Nicotinic receptors on rat alveolar macrophages dampen ATP-induced increase in cytosolic calcium concentration
AU - Mikulski, Zbigniew
AU - Hartmann, Petra
AU - Jositsch, Gitte
AU - Zasłona, Zbigniew
AU - Lips, Katrin S.
AU - Pfeil, Uwe
AU - Kurzen, Hjalmar
AU - Lohmeyer, Jürgen
AU - Clauss, Wolfgang G.
AU - Grau, Veronika
AU - Fronius, Martin
AU - Kummer, Wolfgang
N1 - Funding Information:
The authors wish to thank Ms. Sigrid Wilker and Mr. Martin Bodenbenner for excellent technical assistance, Dr. Gabriela Krasteva for help with the confocal microscopy and Ms. Karola Michael for help with the art work. This study was supported by the DFG (Excellence Cluster “Cardiopulmonary System” and IntGK 1062) and a grant of the University Medical Center Giessen and Marburg.
PY - 2010/9/29
Y1 - 2010/9/29
N2 - Background: Nicotinic acetylcholine receptors (nAChR) have been identified on a variety of cells of the immune system and are generally considered to trigger anti-inflammatory events. In the present study, we determine the nAChR inventory of rat alveolar macrophages (AM), and investigate the cellular events evoked by stimulation with nicotine.Methods: Rat AM were isolated freshly by bronchoalveolar lavage. The expression of nAChR subunits was analyzed by RT-PCR, immunohistochemistry, and Western blotting. To evaluate function of nAChR subunits, electrophysiological recordings and measurements of intracellular calcium concentration ([Ca2+]i) were conducted.Results: Positive RT-PCR results were obtained for nAChR subunits α3, α5, α9, α10, β1, and β2, with most stable expression being noted for subunits α9, α10, β1, and β2. Notably, mRNA coding for subunit α7 which is proposed to convey the nicotinic anti-inflammatory response of macrophages from other sources than the lung was not detected. RT-PCR data were supported by immunohistochemistry on AM isolated by lavage, as well as in lung tissue sections and by Western blotting. Neither whole-cell patch clamp recordings nor measurements of [Ca2+]i revealed changes in membrane current in response to ACh and in [Ca2+]i in response to nicotine, respectively. However, nicotine (100 μM), given 2 min prior to ATP, significantly reduced the ATP-induced rise in [Ca2+]i by 30%. This effect was blocked by α-bungarotoxin and did not depend on the presence of extracellular calcium.Conclusions: Rat AM are equipped with modulatory nAChR with properties distinct from ionotropic nAChR mediating synaptic transmission in the nervous system. Their stimulation with nicotine dampens ATP-induced Ca2+-release from intracellular stores. Thus, the present study identifies the first acute receptor-mediated nicotinic effect on AM with anti-inflammatory potential.
AB - Background: Nicotinic acetylcholine receptors (nAChR) have been identified on a variety of cells of the immune system and are generally considered to trigger anti-inflammatory events. In the present study, we determine the nAChR inventory of rat alveolar macrophages (AM), and investigate the cellular events evoked by stimulation with nicotine.Methods: Rat AM were isolated freshly by bronchoalveolar lavage. The expression of nAChR subunits was analyzed by RT-PCR, immunohistochemistry, and Western blotting. To evaluate function of nAChR subunits, electrophysiological recordings and measurements of intracellular calcium concentration ([Ca2+]i) were conducted.Results: Positive RT-PCR results were obtained for nAChR subunits α3, α5, α9, α10, β1, and β2, with most stable expression being noted for subunits α9, α10, β1, and β2. Notably, mRNA coding for subunit α7 which is proposed to convey the nicotinic anti-inflammatory response of macrophages from other sources than the lung was not detected. RT-PCR data were supported by immunohistochemistry on AM isolated by lavage, as well as in lung tissue sections and by Western blotting. Neither whole-cell patch clamp recordings nor measurements of [Ca2+]i revealed changes in membrane current in response to ACh and in [Ca2+]i in response to nicotine, respectively. However, nicotine (100 μM), given 2 min prior to ATP, significantly reduced the ATP-induced rise in [Ca2+]i by 30%. This effect was blocked by α-bungarotoxin and did not depend on the presence of extracellular calcium.Conclusions: Rat AM are equipped with modulatory nAChR with properties distinct from ionotropic nAChR mediating synaptic transmission in the nervous system. Their stimulation with nicotine dampens ATP-induced Ca2+-release from intracellular stores. Thus, the present study identifies the first acute receptor-mediated nicotinic effect on AM with anti-inflammatory potential.
UR - http://www.scopus.com/inward/record.url?scp=79551602490&partnerID=8YFLogxK
U2 - 10.1186/1465-9921-11-133
DO - 10.1186/1465-9921-11-133
M3 - Article
C2 - 20920278
AN - SCOPUS:79551602490
SN - 1465-9921
VL - 11
JO - Respiratory Research
JF - Respiratory Research
M1 - 133
ER -