Perfect cellular platform for electrophysiology:acutely isolated vagal ganglion neurons from adult canines / 中国药理学与毒理学杂志

OBJECTIVE To establish a platform of electrophysiology using vagal ganglion neurons (VGNs) isolated from adult canines. METHODS The VGNs were enzymatically isolated from adult canines of either gender and cultured under experimental conditions. Action potential (AP), repetitive firing, voltage-gated outward K+ currents (IK) and hyperpolarization-mediated inward currents (Ih) were recorded under current-and voltage-clamp configurations before and after treatment. RESULTS Analysis of AP waveform showed that ① inaddition to traditionally classified myelinated A- and unmyelinated C-types, myelinated Ah-types could also be identified in females rather than in males; ② step current depolarization evoked a stimulus intensity-dependent repetitive discharge, and to reach a similar firing frequency, the lowest stimulus intensity was required for A-types, a similar or slightly higher stimulus intensity was needed for Ah-types, and the highest stimulus intensity was required for C-types;③tetro?dotoxin significantly reduced the rate of depolarization and positively shifted the AP firing threshold of Ah-types, and iberiotoxin dramatically increased the neuroexcitability of Ah-types;④all tested neurons functionally expressed IK and Ih, and the current density for both channels on average was A-types>Ah-types>C-types; ⑤ although the distribution of afferent types of VGNs differed between males and females, the known difference in discharge profiles of A- and C-types isolated from male and female rats was not studied here. CONCLUSION The VGNs can be successfully isolated from adult canines, AP, IK and Ih can be recorded. The tight seal can be held for at least 30 min, which may be enough for pharmacological investigation.

Anti-Hypertensive Action of Fenofibrate via UCP2 Upregulation Mediated by PPAR Activation in Baroreflex Afferent Pathway / 神经科学通报·英文版

Fenofibrate, an agonist for peroxisome proliferator-activated receptor alpha (PPAR-α), lowers blood pressure, but whether this action is mediated via baroreflex afferents has not been elucidated. In this study, the distribution of PPAR-α and PPAR-γ was assessed in the nodose ganglion (NG) and the nucleus of the solitary tract (NTS). Hypertension induced by drinking high fructose (HFD) was reduced, along with complete restoration of impaired baroreceptor sensitivity, by chronic treatment with fenofibrate. The molecular data also showed that both PPAR-α and PPAR-γ were dramatically up-regulated in the NG and NTS of the HFD group. Expression of the downstream signaling molecule of PPAR-α, the mitochondrial uncoupling protein 2 (UCP2), was up-regulated in the baroreflex afferent pathway under similar experimental conditions, along with amelioration of reduced superoxide dismutase activity and increased superoxide in HFD rats. These results suggest that chronic treatment with fenofibrate plays a crucial role in the neural control of blood pressure by improving baroreflex afferent function due at least partially to PPAR-mediated up-regulation of UCP2 expression and reduction of oxidative stress.

Optimizing Imaging Quality and Radiation Dose by the Age-Dependent Setting of Tube Voltage in Pediatric Chest Digital Radiography

OBJECTIVE: The quality and radiation dose of different tube voltage sets for chest digital radiography (DR) were compared in a series of pediatric age groups. MATERIALS AND METHODS: Forty-five hundred children aged 0-14 years (yr) were randomly divided into four groups according to the tube voltage protocols for chest DR: lower kilovoltage potential (kVp) (A), intermediate kVp (B), and higher kVp (C) groups, and the fixed high kVp group (controls). The results were analyzed among five different age groups (0-1 yr, 1-3 yr, 3-7 yr, 7-11 yr and 11-14 yr). The dose area product (DAP) and visual grading analysis score (VGAS) were determined and compared by using one-way analysis of variance. RESULTS: The mean DAP of protocol C was significantly lower as compared with protocols A, B and controls (p < 0.05). DAP was higher in protocol A than the controls (p <0.001), but it was not statistically significantly different between B and the controls (p = 0.976). Mean VGAS was lower in the controls than all three protocols (p < 0.001 for all). Mean VGAS did not differ between protocols A and B (p = 0.334), but was lower in protocol C than A (p = 0.008) and B (p = 0.049). CONCLUSION: Protocol C (higher kVp) may help optimize the trade-off between radiation dose and image quality, and it may be acceptable for use in a pediatric age group from these results.