Direct evidence regarding ion channel-mediated initiation of baroreflex/visceral neurotransmission remains limited.Here,aortic-arch,vagus-nodose slice,and isolated neurons were employed with single-fiber/whole-cell pa...Direct evidence regarding ion channel-mediated initiation of baroreflex/visceral neurotransmission remains limited.Here,aortic-arch,vagus-nodose slice,and isolated neurons were employed with single-fiber/whole-cell patch-clamp recordings to record instantaneous discharge of the aortic depressor nerve,spontaneous/evoked membrane depolarizations under different pharmacological interventions.Strikingly,profiles of A-fiber’s instantaneous firing frequency(IFF),including pressure threshold,rate,and sensitivity,were significantly reduced by 10µmol/L flufenamic acid(FAA)and further suppressed by 3µmol/L GsMTx4.Conversely,3µmol/L Yoda1-enhanced IFF was reversed by GsMTx4 and partially inhibited by FAA,consistent with step depolarization-evoked action potentials(APs).In<10%of A-type neurons,spontaneous APs accompanied by major(Ma-STPs)and minor sub-threshold depolarizations(Mi-STPs)were abolished by nanomolar tetrodotoxin.FAA only blocked spontaneous APs,while GsMTx4 suppressed both APs and Ma-STPs.The equal number of APs and Ma-STPs before and after FAA suggests that spontaneous APs initiate from Ma-STPs.Further,single-cell transcriptomic analysis revealed significant Piezo1 and TRPM4 co-expression in neurons.Gene co-expression and clustering analysis support their cooperative role in the baroreflex and visceral afferent pathways,validated by gene expression data.These findings demonstrate that TTX-sensitive Na+(TTX-S),Piezo1,and TRPM4 channels each possess important intrinsic functions and play unique roles in the initiation of baroreflex/visceral neurotransmission.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.81971326 and 81573431)partially supported by the Heilongjiang Provincial Research Institute Project(No.CZKYF2024-1-A003).
文摘Direct evidence regarding ion channel-mediated initiation of baroreflex/visceral neurotransmission remains limited.Here,aortic-arch,vagus-nodose slice,and isolated neurons were employed with single-fiber/whole-cell patch-clamp recordings to record instantaneous discharge of the aortic depressor nerve,spontaneous/evoked membrane depolarizations under different pharmacological interventions.Strikingly,profiles of A-fiber’s instantaneous firing frequency(IFF),including pressure threshold,rate,and sensitivity,were significantly reduced by 10µmol/L flufenamic acid(FAA)and further suppressed by 3µmol/L GsMTx4.Conversely,3µmol/L Yoda1-enhanced IFF was reversed by GsMTx4 and partially inhibited by FAA,consistent with step depolarization-evoked action potentials(APs).In<10%of A-type neurons,spontaneous APs accompanied by major(Ma-STPs)and minor sub-threshold depolarizations(Mi-STPs)were abolished by nanomolar tetrodotoxin.FAA only blocked spontaneous APs,while GsMTx4 suppressed both APs and Ma-STPs.The equal number of APs and Ma-STPs before and after FAA suggests that spontaneous APs initiate from Ma-STPs.Further,single-cell transcriptomic analysis revealed significant Piezo1 and TRPM4 co-expression in neurons.Gene co-expression and clustering analysis support their cooperative role in the baroreflex and visceral afferent pathways,validated by gene expression data.These findings demonstrate that TTX-sensitive Na+(TTX-S),Piezo1,and TRPM4 channels each possess important intrinsic functions and play unique roles in the initiation of baroreflex/visceral neurotransmission.
