Selective Expression of a Persistent Tetrodotoxin-Resistant Na+Current and NaV1.9 Subunit in Myenteric Sensory Neurons

摘要: Voltage-gated Na + currents play critical roles in shaping electrogenesis neurons. Here, we have identified a TTX-resistant current (TTX-R I ) duodenum myenteric neurons of guinea pig and rat sought evidence regarding the molecular identity channel producing this from expression α subunits biophysical pharmacological properties TTX-R . Whole-cell patch-clamp recording situ revealed presence voltage-gated that was highly resistant to TTX (IC 50 , ∼200 μm) selectively distributed sensory but not interneurons motor activated slowly response depolarization exhibited threshold for activation at –50 mV. V 1/2 values steady-state inactivation were –32 –31 mV absence fluoride, respectively, which, as predicted window current, generated persistent currents. also had prominent ultraslow inactivation, which turns off 50% conductance rest (–60 mV). Substituting CsF CsCl intracellular solution shifted voltage-dependent parameters leftward by ∼20 Under these conditions, similar those reported previously NaN/Na 1.9 dorsal root ganglion Consistent with this, reverse transcription-PCR, single-cell profiling, immunostaining experiments indicated transcripts subunits, 1.8, expressed enteric nervous system restricted may an important role regulating subthreshold boosting synaptic stimuli, thereby conferring distinct integrative