After depletion of intracellular Ca^(2+)stores the capacitative response triggers an extracellular Ca^(2+)influx through store-operated channels(SOCs)which refills these stores.Our objective was to explore if human um...After depletion of intracellular Ca^(2+)stores the capacitative response triggers an extracellular Ca^(2+)influx through store-operated channels(SOCs)which refills these stores.Our objective was to explore if human umbilical artery smooth muscle presented this response and if it was involved in the mechanism of serotonin-and histamine-induced contractions.Intracellular Ca^(2+)depletion by a Ca^(2+)-free extracellular solution followed by Ca^(2+)readdition produced a contraction in artery rings which was inhibited by the blocker of Orai and TRPC channels 2-aminoethoxydiphenyl borate(2-APB),suggesting a capacitative response.In presence of 2-APB the magnitude of a second paired contraction by serotonin or histamine was significantly less than a first one,likely because 2-APB inhibited store refilling by capacitative Ca^(2+)entry.2-APB inhibition of sarcoplasmic reticulum Ca^(2+)release was excluded because this blocker did not affect serotonin force development in a Ca^(2+)-free solution.The PCR technique showed the presence of mRNAs for STIM proteins(1 and 2),for Orai proteins(1,2 and 3)and for TRPC channels(subtypes 1,3,4 and 6)in the smooth muscle of the human umbilical artery.Hence,this artery presents a capacitative contractile response triggered by stimulation with physiological vasoconstrictors and expresses mRNAs for proteins and channels previously identified as SOCs.展开更多
Objective Melittin is the main peptide in bee venom and causes both persistent spontaneous nociception and pain hypersensitivity. Our recent studies indicated that both transient receptor potential （TRP） vanilloid r...Objective Melittin is the main peptide in bee venom and causes both persistent spontaneous nociception and pain hypersensitivity. Our recent studies indicated that both transient receptor potential （TRP） vanilloid receptor 1 （TRPV 1） and canonical TRPs （TRPCs） are involved in mediating the melittin-induced activation of different subpopulations of pri- mary nociceptive cells. Here, we further determined whether TRPC channels are involved in melittin-induced inflamma- tory nociceptive responses in behavioral assays. Methods The anti-nociceptive and anti-hyperalgesic effects of localized peripheral administration of three doses of the non-selective TRPC antagonist, SKF-96365 （1-{[3-[3-（4-methoxyphenyl） propoxy]-4-methoxyphenyl}-lH-imidazole hydrochloride）, were evaluated in melittin tests. Pain-related behaviors were rated by counting the number of paw flinches, and measuring paw withdrawal thermal latency （s） and paw withdrawl me- chanical threshold （g）, over a l-h time-course. Results Localized peripheral SKF-96365 given before melittin prevented, and given after melittin significantly suppressed, the melittin-evoked persistent spontaneous nociception. Pre-blockade and post-suppression of activation of primary nociceptive activity resulted in decreased hypersensitivity to both thermal and mechanical stimuli applied to the primary injury site of the ipsilateral hindpaw, despite dose-effect differences between thermal and mechanical hyperalgesia. However, local administration of SKF-96365 into the contralateral hindpaw had no significant effect on any pain-associated behaviors. In addition, SKF-96365 had no effect on baseline threshold for either thermal or mechanical sensitivity under normal conditions. Conclusion Besides TRPV1, SKF-96365-sensitive TRPC channels might also be involved in the pathophysiological processing of melittin-induced inflammatory pain and hyper- sensitivity. Therapeutically, SKF-96365 is equally effective in preventing primary thermal and mechanical hyperalgesia as well as persistent spontaneous nociception. However, this drug is likely to be more effective in the relief of thermal hyper- algesia than mechanical hyperalgesia when applied 5 min after establishment of primary afferent activation.展开更多
Photouncaging of second messengers has been successfully employed to gain mechanistic insight of cellular signaling path- ways. One of the most enigmatic processes of ion channel regulation is lipid recognition and li...Photouncaging of second messengers has been successfully employed to gain mechanistic insight of cellular signaling path- ways. One of the most enigmatic processes of ion channel regulation is lipid recognition and lipid-gating of TRPC channels, which represents pivotal mechanisms of cellular Ca2＋ homeostasis. Recently, optopharmacological tools including caged lipid mediators became available, enabling an unprecedented level of temporal and spatial control of the activating lipid species within a cellular environment. Here we tested a commonly used caged ligand approach for suitability to investigate TRPC sig- naling at the level of membrane conductance and cellular Ca2＋ handling. We report a specific photouncaging artifact that is triggered by the cage structure coumarin at UV illumination. Electrophysiological characterization identified a light-dependent membrane effect of coumarin. UV light （340 nm） as used for photouncaging, initiated a membrane conductance specifically in the presence of coumarin as low as 30 pmol L-1 concentrations. This conductance masked the TRPC3 conductance evoked by photouncaging, while TRPC-mediated cellular Ca2＋ responses were largely preserved. The observed light-induced membrane effects of the released caging moiety may well interfere with certain cellular functions, and prompt caution in using couma- fin-caged second messengers in cellular studies.展开更多
基金supported by the grant PIP 0202 from the Consejo Nacional de Investigaciones Científicas y Técnicas(CONICET),Argentina.
文摘After depletion of intracellular Ca^(2+)stores the capacitative response triggers an extracellular Ca^(2+)influx through store-operated channels(SOCs)which refills these stores.Our objective was to explore if human umbilical artery smooth muscle presented this response and if it was involved in the mechanism of serotonin-and histamine-induced contractions.Intracellular Ca^(2+)depletion by a Ca^(2+)-free extracellular solution followed by Ca^(2+)readdition produced a contraction in artery rings which was inhibited by the blocker of Orai and TRPC channels 2-aminoethoxydiphenyl borate(2-APB),suggesting a capacitative response.In presence of 2-APB the magnitude of a second paired contraction by serotonin or histamine was significantly less than a first one,likely because 2-APB inhibited store refilling by capacitative Ca^(2+)entry.2-APB inhibition of sarcoplasmic reticulum Ca^(2+)release was excluded because this blocker did not affect serotonin force development in a Ca^(2+)-free solution.The PCR technique showed the presence of mRNAs for STIM proteins(1 and 2),for Orai proteins(1,2 and 3)and for TRPC channels(subtypes 1,3,4 and 6)in the smooth muscle of the human umbilical artery.Hence,this artery presents a capacitative contractile response triggered by stimulation with physiological vasoconstrictors and expresses mRNAs for proteins and channels previously identified as SOCs.
基金supported by grants from the National Natural Science Foundation of China (30770668, 81070899, and 81171049)
文摘Objective Melittin is the main peptide in bee venom and causes both persistent spontaneous nociception and pain hypersensitivity. Our recent studies indicated that both transient receptor potential （TRP） vanilloid receptor 1 （TRPV 1） and canonical TRPs （TRPCs） are involved in mediating the melittin-induced activation of different subpopulations of pri- mary nociceptive cells. Here, we further determined whether TRPC channels are involved in melittin-induced inflamma- tory nociceptive responses in behavioral assays. Methods The anti-nociceptive and anti-hyperalgesic effects of localized peripheral administration of three doses of the non-selective TRPC antagonist, SKF-96365 （1-{[3-[3-（4-methoxyphenyl） propoxy]-4-methoxyphenyl}-lH-imidazole hydrochloride）, were evaluated in melittin tests. Pain-related behaviors were rated by counting the number of paw flinches, and measuring paw withdrawal thermal latency （s） and paw withdrawl me- chanical threshold （g）, over a l-h time-course. Results Localized peripheral SKF-96365 given before melittin prevented, and given after melittin significantly suppressed, the melittin-evoked persistent spontaneous nociception. Pre-blockade and post-suppression of activation of primary nociceptive activity resulted in decreased hypersensitivity to both thermal and mechanical stimuli applied to the primary injury site of the ipsilateral hindpaw, despite dose-effect differences between thermal and mechanical hyperalgesia. However, local administration of SKF-96365 into the contralateral hindpaw had no significant effect on any pain-associated behaviors. In addition, SKF-96365 had no effect on baseline threshold for either thermal or mechanical sensitivity under normal conditions. Conclusion Besides TRPV1, SKF-96365-sensitive TRPC channels might also be involved in the pathophysiological processing of melittin-induced inflammatory pain and hyper- sensitivity. Therapeutically, SKF-96365 is equally effective in preventing primary thermal and mechanical hyperalgesia as well as persistent spontaneous nociception. However, this drug is likely to be more effective in the relief of thermal hyper- algesia than mechanical hyperalgesia when applied 5 min after establishment of primary afferent activation.
基金supported by the Austrian Science Fund(FWFW 1226-B18)
文摘Photouncaging of second messengers has been successfully employed to gain mechanistic insight of cellular signaling path- ways. One of the most enigmatic processes of ion channel regulation is lipid recognition and lipid-gating of TRPC channels, which represents pivotal mechanisms of cellular Ca2＋ homeostasis. Recently, optopharmacological tools including caged lipid mediators became available, enabling an unprecedented level of temporal and spatial control of the activating lipid species within a cellular environment. Here we tested a commonly used caged ligand approach for suitability to investigate TRPC sig- naling at the level of membrane conductance and cellular Ca2＋ handling. We report a specific photouncaging artifact that is triggered by the cage structure coumarin at UV illumination. Electrophysiological characterization identified a light-dependent membrane effect of coumarin. UV light （340 nm） as used for photouncaging, initiated a membrane conductance specifically in the presence of coumarin as low as 30 pmol L-1 concentrations. This conductance masked the TRPC3 conductance evoked by photouncaging, while TRPC-mediated cellular Ca2＋ responses were largely preserved. The observed light-induced membrane effects of the released caging moiety may well interfere with certain cellular functions, and prompt caution in using couma- fin-caged second messengers in cellular studies.
文摘瞬时受体电位C(transient receptor potential canonical,TRPC)通道作为一类重要的非选择性阳离子通道,在心脏具有广泛的分布和表达。TRPC通道通过改变细胞膜电位和介导钙离子(Ca2+)内流对心脏的生理和病理反应产生重要影响。细胞内Ca2+不仅在心肌细胞的兴奋-收缩偶联中发挥重要作用,而且与各类心脏疾病发生密切相关。最近研究发现,TRPC通道可以通过调节细胞内Ca2+变化,与钙调磷酸酶(calcineurin,Ca N)和活化的T细胞核因子(nuclear factor of activated T cells,NFAT)等效应因子参与心肌肥厚的发生发展过程,同时可诱导其他心脏疾病(如心肌纤维化、心率失常、心力衰竭)的发生。本文根据相关研究,围绕TRPC通道在心肌肥厚及相关心脏疾病的发生发展中的作用进行总结回顾。
