Search

Abstract: The direct impact of solar activity on climate has been widely studied through Total Solar Irradiance (TSI). Biological processes also impact climate and are deeply affected by TSI. Marine phytoplankton emissions into the atmosphere have been proposed to change cloud albedo through cloud formation. In this work, we use wavelet analysis to investigate the decadal relation between high-latitude concentrations of methane sulphonic acid, a product of seawater algae, and TSI. We found that some of the methane sulphonic acid main periodicities coincide with periods of solar activity periods. [Copyright &y& Elsevier]

Abstract: The sphenopalatine ganglion (SPG) is the main parasympathetic ganglion that is involved in regulating cerebral vascular tone and gland secretion. SPG neurons have been implicated in some types of migraine headaches but their precise role has yet to be determined. In addition, very little information is available regarding ion channel modulation by neurotransmitters that are involved in the parasympathetic drive of SPG neurons. In this study, acute isolation of adult rat SPG neurons was developed in order to begin the electrophysiological characterization of this ganglion. Under our dissociation conditions, the average number of neurons obtained per ganglion was greater than 1200. Immunofluorescence imaging results showed positive labeling with acethylcholinesterase (AChE), confirming the parasympathetic nature of SPG neurons. On the other hand, weak tyrosine hydroxylase immunostaining was observed in these neurons. Whole-cell patch-clamp recordings revealed that most of the Ca2+ current is carried by N-type (53%) and SNX-482 resistant R-type (30%) Ca2+ channels. In addition, Ca2+ currents were inhibited in a voltage-dependent manner following exposure to oxotremorine-M (Oxo-M), norepinephrine and ATP via muscarinic acetylcholine receptor 2 (M2 AChR) subtype, adrenergic and P2Y purinergic receptors, respectively. The peptides VIP and angiotensin II failed to modulate Ca2+ currents, suggesting that these receptors are not present on the SPG soma or do not couple to Ca2+ channels. In summary, our data suggest that the Ca2+ current inhibition mediated by Oxo-M, NE and ATP in adult rat SPG neurons plays an integral part in maintaining parasympathetic control of cranial functions. [Copyright &y& Elsevier]

The nodose ganglion (NG) is the main parasympathetic ganglion conveying sensory signals to the CNS from numerous visceral organs including digestive signals such as gastric distension or the release the gastrointestinal peptides. The response characteristics of NG neurons to ATP and ADP and pharmacological interrogation of purinergic receptor subtypes have been previously investigated but often in NG cells of undetermined visceral origin. In this study, we confirmed the presence of P2X3 and P2Y1 receptors and characterized P2X and P2Y responses in gastric-innervating NG neurons. Application of ATP-evoked large inward currents and cytosolic Ca2+ increases in gastric-innervating NG neurons. Despite the expression of P2Y1 receptors, ADP elicited only minor modulation of voltage-gated Ca2+ channels. Considering the sensitivity of NG neurons to comorbidities associated with disease or neural injury, purinergic modulation of gastric NG neurons in disease- or injury-states is worthy of further investigation. [ABSTRACT FROM AUTHOR]

The nociceptin/orphanin FQ peptide (NOP) opioid receptors regulate neurotransmitter release via inhibition of voltage-gated Ca 2+ channels (Ca V 2.2) in sympathetic and sensory neurons. Stimulation of NOP receptors by its endogenous agonist, nociception (Noc), leads to membrane-delimited, voltage-dependent (VD) block of Ca V 2.2 channel currents mediated by Gβγ protein subunits. Previously we reported that the pertussis toxin-sensitive Gαi1 and Gβ2/β4 isoforms mediate the functional coupling of NOP opioid receptors with Ca V channels in rat stellate ganglion (SG) sympathetic neurons. In the present report we extended our studies by identifying the Gγ subunit that forms the heterotrimer within this signaling pathway. Small interference RNA (or siRNA) was employed to silence the expression of the natively expressed Gγ subunits. Initial PCR assays indicated that SG neurons expressed seven Gγ subunits. Silencing Gγ3 subunits did not alter signaling between NOP receptors and Ca 2+ channels. However, after Gγ7 isoforms were silenced, the Noc-mediated inhibition of Ca V channels was significantly decreased when compared to SG neurons transfected with scrambled siRNA. We observed that Gγ10 and Gγ11 mRNA levels increased 2.5- and 2.7-fold, respectively, after Gγ7 subunits were silenced. However, this compensatory increase in mRNA expression did not appear to fully rescue the NOP receptor coupling efficiency. Additionally, both Gγ2 and Gγ5 levels increased 50 and 75%, respectively, while Gγ3 and Gγ4 expression levels remained relatively unchanged. Taken together, our findings suggest that the Gαi1/Gβ2(β4)/Gγ7 heterotrimeric G protein complex determines the NOP receptor-mediated modulation of Ca V channels in SG neurons. [ABSTRACT FROM AUTHOR]

The single nucleotide polymorphism of the μ-opioid receptor, OPRM1 A118G, has been associated with greater drug and alcohol use, increased sensitivity to pain, and reduced sensitivity to the antinociceptive effects of opiates. In the present studies, we employed a ‘humanized’ mouse model containing the wild-type (118AA) or variant (118GG) allele to examine behavior in a model of heroin-induced devaluation of an otherwise palatable saccharin cue when repeated saccharin-heroin pairings occurred every 24 h (Experiment 1) or every 48 h (Experiment 2). The results showed that, while both the 118AA and 118GG mice demonstrated robust avoidance of the heroin-paired saccharin cue following daily taste-drug pairings, only the 118AA mice suppressed intake of the heroin-paired saccharin cue when 48 h elapsed between each taste-drug pairing. Humanized 118GG mice, then, defend their intake of the sweet cue despite saccharin-heroin pairings and this effect is illuminated by the use of spaced, rather than massed, trials. Given that this pattern of strain difference is not evident with saccharin-cocaine pairings (Freet et al., 2015), reduced avoidance of the heroin-paired saccharin cue by the 118GG mice may be due to an interaction between the opiate and the subjects’ drive for the sweet or, alternatively, to differential downstream sensitivity to the aversive kappa mediated properties of the drug. These alternative hypotheses are addressed. [ABSTRACT FROM AUTHOR]

Several studies have shown that human carriers of the single nucleotide polymorphism of the μ-opioid receptor, OPRM1 A118G, exhibit greater drug and alcohol use, increased sensitivity to pain, and reduced sensitivity to the antinociceptive effects of opiates. In the present study, we employed a ‘humanized’ mouse model containing the wild-type (118AA) or variant (118GG) allele to examine behavior in our model of drug-induced suppression of a natural reward cue and to compare the morphine pharmacological profile in acutely isolated sensory neurons. Compared with 118AA mice, our results demonstrate that homozygous 118GG mice exhibit greater avoidance of the cocaine-paired saccharin cue, a behavior linked to an aversive withdrawal-like state. Electrophysiological recordings confirmed the reduced modulation of Ca 2 + channels by morphine in trigeminal ganglion (TG) neurons from 118GG mice compared to the 118AA control cells. However, repeated cocaine exposure in 118GG mice led to a leftward shift of the morphine concentration–response relationship when compared with 118GG control mice, while a rightward shift was observed in 118AA mice. These results suggest that cocaine exposure of mice carrying the 118G allele leads to a heightened sensitivity of the reward system and a blunted modulation of Ca 2 + channels by morphine in sensory neurons. [ABSTRACT FROM AUTHOR]

Highlights: [•] A803467 (1mg) reduced pressor responses to stimulation of group III & IV afferents. [•] A803467 (1mg) reduced muscle spindle activity to stretch and succinylcholine. [•] The utility of A803467 in vivo is challenged as a selective antagonist for NaV 1.8. [Copyright &y& Elsevier]

Summary: Background: Haemophilus influenzae type b (Hib) conjugate vaccine reduces the risk of pneumonia in infants. Objective: To determine the effect of Hib conjugate vaccine (HibCV) on the prevention of pneumonia as a complication among infants hospitalized for bronchiolitis. Methods: This record-based case–control study was conducted at The Children''s Hospital “Dr. Ovidio Aliaga U” in La Paz, Bolivia during 2003 and 2004. Cases were infants hospitalized for bronchiolitis under 1 year of age who developed radiological pneumonia during hospitalization. Controls were patients who had good clinical progress without the use of antibiotics. Pneumonia was defined by alveolar consolidation on chest X-ray that justified the use of antibiotics. Results: Eighty patients were studied (16 cases and 64 controls). Their median age was 4.5 months. Demographic and clinical features were similar in both groups, except for a higher proportion of vomiting (56.3% vs. 28.1%; p <0.05) in the case group. The percentage of unvaccinated infants was significantly higher in cases (68.8% vs. 26.6%; p <0.05) and the length of hospital stay longer (8.5±5.4 vs. 3.1±2.2 days; p <0.05). There was a strong association between unvaccinated infants and the occurrence of pneumonia as a complication (odds ratio 6.1, 95% confidence interval 1.8–20.1; p <0.01). Conclusions: Unvaccinated infants admitted for bronchiolitis have a higher risk of radiologically confirmed pneumonia. Larger studies are needed to validate these results and reconsider the burden of Hib infection among infants in less developed countries. [Copyright &y& Elsevier]

Abstract: The 20th century surface air temperature (SAT) records of China from various sources are analyzed using data which include the recently released Twentieth Century Reanalysis Project dataset. Two key features of the Chinese records are confirmed: (1) significant 1920s and 1940s warming in the temperature records, and (2) evidence for a persistent multidecadal modulation of the Chinese surface temperature records in co-variations with both incoming solar radiation at the top of the atmosphere as well as the modulated solar radiation reaching ground surface. New evidence is presented for this Sun–climate link for the instrumental record from 1880 to 2002. Additionally, two non-local physical aspects of solar radiation-induced modulation of the Chinese SAT record are documented and discussed. Teleconnections that provide a persistent and systematic modulation of the temperature response of the Tibetan Plateau and/or the tropospheric air column above the Eurasian continent (e.g., 30°N–70°N; 0°–120°E) are described. These teleconnections may originate from the solar irradiance-Arctic–North Atlantic overturning circulation mechanism proposed by . Also considered is the modulation of large-scale land–sea thermal contrasts both in terms of meridional and zonal gradients between the subtropical western Pacific and mid-latitude North Pacific and the continental landmass of China. The Circum-global teleconnection (CGT) pattern of summer circulation of provides a physical framework for study of the Sun–climate connection over East Asia. Our results highlight the importance of solar radiation reaching the ground and the concomitant importance of changes in atmospheric transparency or cloudiness or both in motivating a true physical explanation of any Sun–climate connection. We conclude that ground surface solar radiation is an important modulating factor for Chinese SAT changes on multidecadal to centennial timescales. Therefore, a comprehensive view of local and remote factors of climate change in China must take account of this as well as other natural and anthropogenic forcings. [Copyright &y& Elsevier]

Stellate ganglion (SG) neurons provide the main sympathetic innervation to the heart and help to regulate cardiac function. The purpose of this study was to determine if ultrasound imaging could be employed to retrograde label rat SG neurons innervating the heart without employing thoracotomy. In addition, electrophysiological experiments were performed to characterize the modulation of Ca2+ channels by neurotransmitters in unlabeled and dye-labeled SG neurons. Fluorescence imaging of actutely isolated cells revealed that dye uptake was successful within five days following injection of dye in the cardiac muscle. Whole-cell voltage-clamp recordings revealed that the majority of the Ca2+ current was carried by N-type Ca2+ channels. Finally, fluorescence dye uptake did not appear to affect the modulation of Ca2+ currents following exposure of SG neurons to norepinephrine, adenosine and neurokinin A. These results demonstrate that ultrasound imaging-guided percutaneous injection can be effectively employed to retrograde label neurons innervating the heart. [Copyright &y& Elsevier]