Recent studies suggest that certain acid-sensing ion channels (ASIC) are expressed in vascular smooth muscle cells (VSMCs) and are required for VSMC functions. However, electrophysiological evidence of ASIC channels in VSMCs is lacking. The purpose of this study was to test the hypothesis that isolated cerebral artery VSMCs express ASIC-like channels. To address this hypothesis, we used RT-PCR, Western blotting, immunolabeling, and conventional whole cell patch-clamp technique. We found extracellular H+-induced inward currents in 46% of cells tested ( n = 58 of 126 VSMCs, pH 6.5–5.0). The percentage of responsive cells and the current amplitude increased as the external H+ concentration increased (pH6.0, n = 28/65 VSMCs responsive, mean current density = 8.1 ± 1.2 pA/pF). Extracellular acidosis (pH6.0) shifted the whole cell reversal potential toward the Nernst potential of Na+ ( n = 6) and substitution of extracellular Na+ by N-methyl-d-glucamine abolished the inward current ( n = 6), indicating that Na+ is a major charge carrier. The broad-spectrum ASIC blocker amiloride (20 μM) inhibited proton-induced currents to 16.5 ± 8.7% of control ( n = 6, pH6.0). Psalmotoxin 1 (PcTx1), an ASIC1a inhibitor and ASIC1b activator, had mixed effects: PcTx1 either 1) abolished H+-induced currents (11% of VSMCs, 5/45), 2) enhanced or promoted activation of H+-induced currents (76%, 34/45), or 3) failed to promote H+ activation in nonresponsive VSMCs (13%, 6/45). These findings suggest that freshly dissociated cerebral artery VSMCs express ASIC-like channels, which are predominantly formed by ASIC1b.

BackgroundExpedited partner therapy (EPT) for chlamydia can be an important public health tool to treat the sex partners of newly diagnosed individuals, especially when those sex partners are women of reproductive ages. Untreated and repeat chlamydia infections increase a woman’s risk for subfertility. This study aimed to determine the knowledge of EPT, and the factors associated with EPT knowledge, among reproductive-aged women.MethodsWomen aged 18–40 years were recruited for a community sample from a large state fair; 871 women completed a questionnaire for this study. Women reported on their knowledge of sexually transmitted infections, and about their knowledge and attitudes toward EPT. Using a hypothetical example, women were asked if they would accept EPT.ResultsThis community sample of reproductive-aged women found overwhelming hypothetical support for chlamydia testing, partner notification, and partner treatment. However, only 12% of women reported having heard of EPT prior to the survey; once EPT was described, there were high levels of support for EPT and the belief that EPT could reduce chlamydia rates. Half of the women strongly agreed that EPT could reduce chlamydia rates, and 48% supported the state law allowing for EPT. Working in the healthcare field was the only independent determinant of prior EPT knowledge, increasing the odds of hearing about EPT by more than 2.5-fold.ConclusionsDespite overwhelming support of the tenets of EPT, our results indicate that prior knowledge of EPT is low among women, meaning that education about EPT is needed for those outside of the healthcare field.

Our laboratory has demonstrated the presence of acid‐sensing ion channels (ASIC)‐like currents in freshly isolated cerebral vascular smooth muscle cells (VSMC). In these cells, extracellular H+ (pH≤6.5) induces an amiloride‐sensitive inward Na+ current. However, the ASIC subunits mediating this response are unknown. In this study, Western blotting and immunostaining demonstrated robust expression of ASIC1b, although other subunits were also detected to a lesser extent. Patchclamp was utilized to determine if ASIC1b may mediate H+‐gated currents; we evaluated responses to psalmotoxin 1 (PcTX1, 100nM), a known inhibitor and activator of ASIC1a and ASIC1b channels, respectively. In voltage‐clamped VSMCs, PcTX1 inhibited H+‐induced (pH 6.0) inward current in only 4 of 44 VSMCs examined. PcTX1 enhanced currents in 34/44 VSMCs by 12.0±2.7 pA/pF (p<0.001) and increased the mean desensitization constant of the initial decline phase of peak current (2.2±0.3 to 4.7±0.9 s; p<0.05; n=15). Taken together, these findings suggest that ASIC1b conducts most H+ gated currents in freshly isolated VSMC.