TY - JOUR
T1 - Capsaicin inhibits the function of α7-nicotinic acetylcholine receptors expressed in Xenopus oocytes and rat hippocampal neurons.
AU - Alzaabi, Asma Hassan
AU - Howarth, Luke
AU - El Nebrisi, Eslam
AU - Syed, Nurulain
AU - Susan Yang, Keun Hang
AU - Howarth, Frank Christopher
AU - Oz, Murat
N1 - Funding Information:
The research in this study was supported by grants from CMHS and UAE University . The authors gratefully acknowledge Dr. Jon Lindstrom (University of Pennsylvania, PA, USA) for providing cDNA clones of the human α 7 -nACh receptor subunit, Dr. Isabel Bermudez-Diaz (Oxford Brookes University, Oxford, UK) for human α 4 , α 3 , β 2 , and β 4 subunits.
Publisher Copyright:
© 2019 Elsevier B.V.
PY - 2019/8/15
Y1 - 2019/8/15
N2 - Capsaicin is a naturally occurring alkaloid derived from Chili peppers fruits. Using the two-electrode voltage-clamp technique in Xenopus oocyte expression system, actions of capsaicin on the functional properties of α7 subunit of the human nicotinic acetylcholine (α7 nACh) receptor were investigated. Ion currents activated by ACh (100 μM) were reversibly inhibited with an IC50 value of 8.6 μM. Inhibitory actions of capsaicin was independent of membrane potential. Furthermore, Ca2+-dependent Cl- channels expressed endogenously in oocytes were not involved in inhibitory actions of capsaicin. In addition, increasing the ACh concentrations could not reverse the inhibitory effects of capsaicin. Importantly, specific binding of [125I] α-bungarotoxin remained unaltered by capsaicin suggesting that its effect is noncompetitive. Whole cell patch-clamp technique was performed in CA1 stratum radiatum interneurons of rat hippocampal slices. Ion currents induced by choline, a selective-agonist of α7-receptor, were reversibly inhibited by 10 min bath application of capsaicin (10 μM). Collectively, results of our investigation indicate that the function of the α7-nACh receptor expressed in Xenopus oocytes and in hippocampal interneurons are inhibited by capsaicin.
AB - Capsaicin is a naturally occurring alkaloid derived from Chili peppers fruits. Using the two-electrode voltage-clamp technique in Xenopus oocyte expression system, actions of capsaicin on the functional properties of α7 subunit of the human nicotinic acetylcholine (α7 nACh) receptor were investigated. Ion currents activated by ACh (100 μM) were reversibly inhibited with an IC50 value of 8.6 μM. Inhibitory actions of capsaicin was independent of membrane potential. Furthermore, Ca2+-dependent Cl- channels expressed endogenously in oocytes were not involved in inhibitory actions of capsaicin. In addition, increasing the ACh concentrations could not reverse the inhibitory effects of capsaicin. Importantly, specific binding of [125I] α-bungarotoxin remained unaltered by capsaicin suggesting that its effect is noncompetitive. Whole cell patch-clamp technique was performed in CA1 stratum radiatum interneurons of rat hippocampal slices. Ion currents induced by choline, a selective-agonist of α7-receptor, were reversibly inhibited by 10 min bath application of capsaicin (10 μM). Collectively, results of our investigation indicate that the function of the α7-nACh receptor expressed in Xenopus oocytes and in hippocampal interneurons are inhibited by capsaicin.
KW - Capsaicin
KW - Hippocampus
KW - Neurons.
KW - Nicotinic receptors
KW - Xenopus oocyte
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U2 - 10.1016/j.ejphar.2019.172411
DO - 10.1016/j.ejphar.2019.172411
M3 - Article
C2 - 31152699
AN - SCOPUS:85066403615
SN - 0014-2999
VL - 857
JO - European Journal of Pharmacology
JF - European Journal of Pharmacology
M1 - 172411
ER -