Ankyrin-rich membrane spanning protein as a novel modulator of transient receptor potential vanilloid 1-function in nociceptive neurons.

BACKGROUND: The ion channel TRPV1 is mainly expressed in small diameter dorsal root ganglion (DRG) neurons, which are involved in the sensation of acute noxious thermal and chemical stimuli. Direct modifications of the channel by diverse signalling events have been intensively investigated, but little is known about the composition of modulating macromolecular TRPV1 signalling complexes. Here, we hypothesize that the novel adaptor protein ankyrin-rich membrane spanning protein/kinase D interacting substrate (ARMS) interacts with TRPV1 and modulates its function in rodent DRG neurons. METHODS: We used immunohistochemistry, electrophysiology, microfluorimetry and immunoprecipitation experiments to investigate TRPV1 and ARMS interactions in DRG neurons and transfected cells. RESULTS: We found that TRPV1 and ARMS are co-expressed in a subpopulation of DRG neurons. ARMS sensitizes TRPV1 towards capsaicin in transfected HEK 293 cells and in mouse DRG neurons in a PKA-dependent manner. Using a combination of functional imaging and immunocytochemistry, we show that the magnitude of the capsaicin response in DRG neurons depends not only on TRPV1 expression, but on the co-expression of ARMS alongside TRPV1. CONCLUSION: These data indicate that ARMS is an important component of the signalling complex regulating the sensitivity of TRPV1. SIGNIFICANCE: The study identifies ARMS as an important component of the signalling complex regulating the sensitivity of excitatory ion channels (TRPV1) in peripheral sensory neurons (DRG neurons) and transfected cells.

Trace formula for chaotic dielectric resonators tested with microwave experiments.

We measured the resonance spectra of two stadium-shaped dielectric microwave resonators and tested a semiclassical trace formula for chaotic dielectric resonators proposed by Bogomolny et al. [Phys. Rev. E 78, 056202 (2008)]. We found good qualitative agreement between the experimental data and the predictions of the trace formula. Deviations could be attributed to missing resonances in the measured spectra in accordance with previous experiments [Phys. Rev. E 81, 066215 (2010)]. The investigation of the numerical length spectrum showed good qualitative and reasonable quantitative agreement with the trace formula. It demonstrated, however, the need for higher-order corrections of the trace formula. The application of a curvature correction to the Fresnel reflection coefficients entering the trace formula yielded better agreement, but deviations remained, indicating the necessity of further investigations.

[Clinical significance of objective vision assessment using visually evoked cortical potentials induced by rapid pattern sequences of different spatial frequency]. / Zur klinischen Bedeutung der objektiven Sehschärfenschätzung mit Hilfe der visuell evozierten kortikalen Potentiale durch schnelle Reizmustersequenzen unterschiedlicher Ortsfrequenz.

BACKGROUND: In patients where reliable subjective assessment of visual acuity is impossible, further diagnostics should be enhanced by an objective method. PATIENTS AND METHODS: A group of 34 patients was examined by objective assessment of visual acuity using visual evoked potentials (VEP) as described by Hajek and Zrenner in 1988. The presentation of five checkerboards with different spatial frequency in repetitive sequences on a TV-monitor elicits a series of transient visual evoked potentials. Shape and amplitude of each wavelet depends on check size and directly reflect a spatial tuning function with a low- and high-frequency cut-off. This amplitude is described by a polynomial fit (2nd order). The function's intersection with the x-axis at higher spatial frequencies leads to an estimation of the visual acuity. RESULT: This result is compared to the subjectively determined visual acuity. In the majority of the presented cases the suspected malingering was confirmed. CONCLUSION: Patients with suspected malingering represent the primary indication of the described method.

Colour vision disturbances in chronic smokers.

PURPOSE: The aim of the present study was to test the influence of smoking on colour perception. SUBJECTS AND METHODS: At the University Eye Hospital Tübingen, 76 generally healthy smokers with inconspicuous ophthalmological findings (visual acuity, refraction, intraocular pressure, morphology) were examined by the cap-sorting test, Roth 28-hue desaturated. Group 1 was comprised of smokers (n = 20; M 9, F 11; mean age 28.1+/-10.3 years) with a smoking consumption of less than one packet of cigarettes per day (8.4+/-5.3 cigarettes/day) for 9.1+/-8.3 years. Group 2 consisted of smokers (n = 32; M 22, F 10; mean age 28.6+/-9.7 years) with a smoking consumption of one or more than one packet per day (30+/-8.4 cigarettes/ day) for 9.5+/-8.3 years. Generally healthy and ophthalmologically normal non-smokers served as a control group (n = 76; M 41, F 35; mean age 30+/-9 years). RESULTS: The average error score of the control group was (median +/- mean absolute deviation) 42+/-18. Group 1 showed no difference to the control group (51+/-27; P = 0.42). On the other hand, group 2 had a significantly higher error score than the control group (102+/-45; P<0.0001). CONCLUSION: Otherwise healthy smokers with a cigarette consumption of less than 20 cigarettes per day do not show any disturbances in colour vision. Smokers who consume more than 20 cigarettes per day may suffer colour vision defects as a result.

Lack of stability in neonatal adrenocortical reactivity because of rapid habituation of the adrenocortical response.

The purpose of the study was to examine the stability of the adrenocortical response to stimulation in the human neonate. Forty-nine healthy newborns were examined twice responding to discharge examinations performed on two consecutive days. The dependent measures were salivary and plasma cortisol and behavioral state. Little evidence of stability was obtained. Instead, the results showed significant elevations in cortisol only in response to the first discharge examination. No significant elevation in cortisol was noted to the second discharge examination although the newborns continued to exhibit behavioral distress. Time since delivery was not a significant factor in producing these results. The findings are discussed with regard to neonatal coping processes and the importance of novelty in regulating increases in adrenocortical activity.

Adrenocortical activity and behavioral distress in human newborns.

The association between behavioral distress and adrenocortical activity was examined in two experiments with human newborns. In Experiment 1, behavioral and adrenocortical responses to 4 events (circumcision, blood sampling, weighing and measuring, and discharge examination) were compared using a between-subject design. All 4 events elicited fussing and crying and elevations in plasma cortisol; however, differences in behavioral distress among conditions did not reliably predict differences in plasma cortisol. In Experiment 2, nonnutritive sucking was used to effectively reduce behavioral distress, but was not associated with a reduction in the adrenocortical response to stimulation. Finally, using data from both experiments, correlations were computed between behavioral distress and cortisol. Both positive and negative associations were found as a function of the type of stressor and the biomedical status of the newborn.

Adrenocortical activity and the Brazelton Neonatal Assessment Scale: moderating effects of the newborn's biomedical status.

The Brazelton Neonatal Behavioral Assessment Scale with Kansas Supplement (NBAS-K) was administered midway between feedings to 60 newborns who were between 32 and 122 hours old. 35 of the newborns were classified as extremely healthy and normal (Subgroup I), whereas 25 (Subgroup II) were characterized by slight perinatal problems including gestational age 36-37 weeks or 42+ weeks, and fetal distress during labor. All of the newborns were healthy enough to be cared for in a healthy newborn, Level I nursery. Immediately following administration of the NBAS-K, a blood sample was obtained for plasma cortisol determination. Correlations between behavioral responding on the NBAS-K and levels of plasma cortisol revealed few significant relations for the sample as a whole. When the 2 subgroups were examined separately, a number of significant relations emerged. Newborns in Subgroup I who were more competent in their motor control and state regulation capacities as assessed by Lester's Cluster Scores for the NBAS-K exhibited higher levels of plasma cortisol. In contrast, newborns in Subgroup II who exhibited a greater adrenocortical response to the examination showed more behaviors indicative of high behavioral arousal and distress. This pattern of relations for Subgroup II appeared to be mediated by the number of hours that had elapsed since delivery. As postpartum time increased, the strength of the association between adrenocortical activity and behavioral arousal/distress decreased for Subgroup II. A systems theory approach is used to interpret the difference in patterns of correlations found for the 2 subgroups.