ATP Injection Research Articles

Investigation into the Mechanism of ATP-Induced Senescence Treated with Hegu and Taichong Electroacupuncture

Objective: The purpose of this study was to clarify the aging mechanism of ATP injection combined with Electroacupuncture at Hegu and Taizhong points, and to provide scientific basis for subsequent clinical research. Methods: 60 rats were randomly divided into 5 groups: control group was injected with normal saline; Model group rats were injected with ATP solution; In the intervention group, the frequency of electroacupuncture was 20Hz, 30Hz and 50Hz, respectively. Electroacupuncture at Hegu Point and Taizhong point once a day for 20 minutes each time. Blood RNA was extracted by TRIzol method, and gene sequencing was performed to identify the differential genes. In addition, the "Senescence" gene data was retrieved from the NCBI gene database and intersected with the sequencing data. The core genes were analyzed by enrichment analysis, module analysis, miRNA-mRNA regulatory network analysis and PCR validation. In addition, cell cycle, apoptosis, ROS levels, and mitochondrial membrane potential were evaluated. Results: DGE analysis found 3,510 DEGs in the sequencing data, of which 3,487 up-regulated genes and 23 down-regulated genes. According to KEGG, These genes are mainly involved in the T cell receptor signaling pathway, Human T−cell leukemia virus 1 infection, Protein processing in endoplasmic reticulum and Phosphatidylinositol signaling system. The 59 common genes of aging identified by Venn diagram analysis, KEGG was mainly involved in AGE−RAGE signaling pathway in diabetic complications, Non−alcoholic fatty liver disease and FoxO signaling pathway and other pathways. Venn diagram is used to show the seven core genes identified by all four algorithms: HSPA4, CASP3, AKT1, PARP1, NFKB1, GSK3B, FOXO3. Electroacupuncture can inhibit apoptosis in ATP-induced aging treatment of rats, and significantly increase mitochondrial membrane potential. In Electro-acupuncture group, cells in G0\G1 cycle significantly increase, and ROS level significantly decrease. Conclusion: Electroacupuncture can inhibit Senescence induced by ATP injection.

Amplified P2X3 pathway activity in muscle afferent dorsal root ganglion neurons and exercise pressor reflex regulation in hindlimb ischaemia-reperfusion.

Hindlimb ischaemia-reperfusion (IR) is among the most prominent pathophysiological conditions observed in peripheral artery disease (PAD). An exaggerated arterial blood pressure (BP) response during exercise is associated with an elevated risk of cardiovascular events in individuals with PAD. However, the precise mechanisms leading to this exaggerated BP response are poorly elucidated. The P2X3 signalling pathway, which plays a key role in modifying the exercise pressor reflex (EPR), is the focus of the present study. We determined the regulatory role of P2X3 on the EPR in a rat model of hindlimb IR. In vivo and in vitro approaches were used to determine the expression and functions of P2X3 in muscle afferent nerves and EPR in IR rats. We found that in IR rats there was (1) upregulation of P2X3 protein expression in the L4-6 dorsal root ganglia (DRG); (2) amplified P2X currents in isolated isolectin B4 (IB4)-positive muscle DRG neurons; and (3) amplification of the P2X-mediated BP response. We further verified that both A-317491 and siRNA knockdown of P2X3 significantly decreased the activity of P2X currents in isolated muscle DRG neurons. Moreover, inhibition of muscle afferents' P2X3 receptor using A-317491 was observed to alleviate the exaggerated BP response induced by static muscle contraction and P2X-induced BP response by α,β-methylene ATP injection. P2X3 signalling pathway activity is amplified in muscle afferent DRG neurons in regulating the EPR following hindlimb IR.

Evaluate the Correlation between the TIMI Frame Count, IMR, and CFR in Coronary Microvascular Disease.

Objective To evaluate the correlation between the TIMI frame count, IMR, and CFR in coronary microvascular disease (slow flow phenomenon). Methods TFC and IMR were recorded in the nitroglycerin and ATP administration states, and the relationship between TFC, IMR, and CFR in specific states was analyzed. Results A total of 41 patients with baseline TFC >25 frames on coronary angiography were enrolled, and nitroglycerin reduced TFC by 50% from baseline in 24 (58.54%) patients; 16 of the remaining 17 patients were able to achieve a 50% reduction in TFC by further intracoronary ATP injection. 10 patients were further tested for IMR, and the results showed significant correlations between baseline TFC and IMR (r = 0.775, P=0.008), TFC and IMR after nitroglycerin (r = 0.875, P=0.001), and the minimal TFC and IMR that could be obtained with nitroglycerin or ATP administration (r = 0.890, P=0.001). There was also a significant correlation between the proportional improvement in TFC and CFR before and after nitroglycerin injection (r = 0.685, P=0.029). In addition, we observed a lower IMR measured after nitroglycerin than after ATP in three patients, suggesting that CMD may be dominated by NO-sensitive vascular such as prearterioles and that an extensive analysis of the target site of CMD may be achieved by stepwise drug administration. Conclusion Induction of TFC in different states by a stepwise drug approach may serve as a potential primary screening method for coronary microcirculatory dysfunction, thereby reducing the need for further IMR or CFR testing.

Progressive Local Accumulation of Self-Assembled Nanoreactors in a Hydrogel Matrix through Repetitive Injections of ATP.

Cellular functions are regulated with high spatial control through the local activation of chemical processes in a complex inhomogeneous matrix. The development of synthetic macroscopic systems with a similar capacity allows fundamental studies aimed at understanding the relationship between local molecular events and the emergence of functional properties at the macroscopic level. Here, we show that a kinetically stable inhomogeneous hydrogel matrix is spontaneously formed upon the local injection of ATP. Locally, ATP templates the self-assembly of amphiphiles into large nanoreactors with a much lower diffusion rate compared to unassembled amphiphiles. The local depletion of unassembled amphiphiles near the injection point installs a concentration gradient along which unassembled amphiphiles diffuse from the surroundings to the center. This allows for a progressive local accumulation of self-assembled nanoreactors in the matrix upon repetitive cycles of ATP injection separated by time intervals during which diffusion of unassembled amphiphiles takes place. Contrary to the homogeneous matrix containing the same components, in the inhomogeneous matrix the local upregulation of a chemical reaction occurs. Depending on the way the same amount of injected ATP is administered to the hydrogel matrix different macroscopic distributions of nanoreactors are obtained, which affect the location in the matrix where the chemical reaction is upregulated.

Catheter ablation of ganglionated plexi in patients with adenosine triphosphate-induced atrial fibrillation after pulmonary vein isolation.

Intravenous ATP may induce atrial fibrillation (AF). ATP shares similar receptor-effector coupling systems with acetylcholine. However, the association between an ATP injection and the hyperactivity of the intrinsic cardiac autonomic nervous system, known as ganglionated plexi (GPs), is not well understood. We describe a series of patients with non-pulmonary vein (PV) trigger sites provoked by an ATP injection, and assess the feasibility of a ganglionated plexus (GP) ablation. We retrospectively analyzed 547 patients (69% male; mean age 67.4 ± 10.4years; 38.5% non-paroxysmal AF) who underwent a total of 604 ablation procedures. Intravenous ATP was administered with an isoproterenol infusion during sinus rhythm after a pulmonary vein isolation in 21.3%, Box isolation in 78.6%, and SVC isolation in 52.0% of the procedures, respectively. We reviewed the incidence, the distribution of the foci, and the ablation outcomes in patients with ATP-induced AF. A total of seven patients (1.3%) had ATP-induced AF. Foci were identified in the coronary sinus (CS) in six patients, right atrial posterior wall (RAPW) adjacent to the interatrial groove in two, mitral annulus in two, ligament of Marshall in one, right septum below the foramen ovale in one and left atrial posterior wall in one, respectively. Among these trigger foci, we confirmed the vagal response by high-frequency stimulation in the CS and RAPW in six and two patients, respectively. After a median RF time of 2.9min (range 2.5-11.3) targeting these foci, in five of six patients who received a repeat ATP injection, the AF became non-inducible. ATP-provoked trigger foci were distributed among certain sites that overlapped with the distribution of the GPs. The GP ablation was effective for this rare, but challenging situation.

Type 2 diabetic mice enter a state of spontaneous hibernation-like suspended animation following accumulation of uric acid

Hibernation is an example of extreme hypometabolic behavior. How mammals achieve such a state of suspended animation remains unclear. Here we show that several strains of type 2 diabetic mice spontaneously enter into hibernation-like suspended animation (HLSA) in cold temperatures. Nondiabetic mice injected with ATP mimic the severe hypothermia analogous to that observed in diabetic mice. We identified that uric acid, an ATP metabolite, is a key molecular in the entry of HLSA. Uric acid binds to the Na+ binding pocket of the Na+/H+ exchanger protein and inhibits its activity, acidifying the cytoplasm and triggering a drop in metabolic rate. The suppression of uric acid biosynthesis blocks the occurrence of HLSA, and hyperuricemic mice induced by treatment with an uricase inhibitor can spontaneously enter into HLSA similar to that observed in type 2 diabetic mice. In rats and dogs, injection of ATP induces a reversible state of HLSA similar to that seen in mice. However, ATP injection fails to induce HLSA in pigs due to the lack of their ability to accumulate uric acid. Our results raise the possibility that nonhibernating mammals could spontaneously undergo HLSA upon accumulation of ATP metabolite, uric acid.

Roles of Cytokines in the Temporal Changes of Microglial Membrane Currents and Neuronal Excitability and Synaptic Efficacy in ATP-Induced Cortical Injury Model.

Cytokines are important neuroinflammatory modulators in neurodegenerative brain disorders including traumatic brain injury (TBI) and stroke. However, their temporal effects on the physiological properties of microglia and neurons during the recovery period have been unclear. Here, using an ATP-induced cortical injury model, we characterized selective effects of ATP injection compared to needle-control. In the damaged region, the fluorescent intensity of CX3CR1-GFP (+) cells, as well as the cell density, was increased and the maturation of newborn BrdU (+) cells continued until 28 day-post-injection (dpi) of ATP. The excitability and synaptic E/I balance of neurons and the inward and outward membrane currents of microglia were increased at 3 dpi, when expressions of tumor necrosis factor (TNF)-α/interleukin (IL)-1β and IL-10/IL-4 were also enhanced. These changes of both cells at 3 dpi were mostly decayed at 7 dpi and were suppressed by any of IL-10, IL-4, suramin (P2 receptor inhibitor) and 4-AP (K+ channel blocker). Acute ATP application alone induced only small effects from both naïve neurons and microglial cells in brain slice. However, TNF-α alone effectively increased the excitability of naïve neurons, which was blocked by suramin or 4-AP. TNF-α and IL-1β increased and decreased membrane currents of naïve microglia, respectively. Our results suggest that ATP and TNF-α dominantly induce the physiological activities of 3 dpi neurons and microglia, and IL-10 effectively suppresses such changes of both activated cells in K+ channel- and P2 receptor-dependent manner, while IL-4 suppresses neurons preferentially.

Metabolic and behavioral features of acute hyperpurinergia and the maternal immune activation mouse model of autism spectrum disorder.

Since 2012, studies in mice, rats, and humans have suggested that abnormalities in purinergic signaling may be a final common pathway for many genetic and environmental causes of autism spectrum disorder (ASD). The current study in mice was conducted to characterize the bioenergetic, metabolomic, breathomic, and behavioral features of acute hyperpurinergia triggered by systemic injection of the purinergic agonist and danger signal, extracellular ATP (eATP). Responses were studied in C57BL/6J mice in the maternal immune activation (MIA) model and controls. Basal metabolic rates and locomotor activity were measured in CLAMS cages. Plasma metabolomics measured 401 metabolites. Breathomics measured 98 volatile organic compounds. Intraperitoneal eATP dropped basal metabolic rate measured by whole body oxygen consumption by 74% ± 6% (mean ± SEM) and rectal temperature by 6.2˚ ± 0.3˚C in 30 minutes. Over 200 metabolites from 37 different biochemical pathways where changed. Breathomics showed an increase in exhaled carbon monoxide, dimethylsulfide, and isoprene. Metabolomics revealed an acute increase in lactate, citrate, purines, urea, dopamine, eicosanoids, microbiome metabolites, oxidized glutathione, thiamine, niacinamide, and pyridoxic acid, and decreased folate-methylation-1-carbon intermediates, amino acids, short and medium chain acyl-carnitines, phospholipids, ceramides, sphingomyelins, cholesterol, bile acids, and vitamin D similar to some children with ASD. MIA animals were hypersensitive to postnatal exposure to eATP or poly(IC), which produced a rebound increase in body temperature that lasted several weeks before returning to baseline. Acute hyperpurinergia produced metabolic and behavioral changes in mice. The behaviors and metabolic changes produced by ATP injection were associated with mitochondrial functional changes that were profound but reversible.

ATP Stimulation Promotes Functional Recovery after Intracerebral Haemorrhage by Increasing the mBDNF/proBDNF Ratio

Brain-derived neurotrophic factor (BDNF), including mature BDNF (mBDNF) and precursor BDNF (proBDNF), plays a pivotal role in neuronal survival, synaptic plasticity and neurogenesis. However, the functional effect of the mBDNF/proBDNF ratio in haemorrhagic stroke remains unclear. ATP is a known mediator of BDNF production in neurons and glia. Therefore, we hypothesized that ATP could facilitate BDNF production, increase the mBDNF/proBDNF ratio and thereby alleviate cerebral haemorrhage-induced injury. In this experiment, a model of intracerebral haemorrhage (ICH) was produced by injecting 50 μL autologous blood into the right corpus striatum in healthy male rats. ATP was injected to promote BDNF production and increase the mBDNF/proBDNF ratio. After ATP pretreatment, P2X4R-shRNA and SB203580 were used to inhibit P2X4R and p38-MAPK, respectively. We provide direct evidence that ATP administration was successful in promoting mBDNF expression and increasing the mBDNF/proBDNF ratio after ICH injury. Additionally, ATP stimulation could significantly improve cerebral neurological function and alleviate neuronal damage. Furthermore, ATP injection was able to upregulate the expression of P2X4R and p-p38-MAPK. Moreover, both P2X4R-shRNA and SB203580 could effectively abolish the effect of ATP injection on the levels of P2X4R and p-p38-MAPK and the mBDNF/proBDNF ratio. Together, these findings show that ATP stimulation contributes to functional recovery after cerebral haemorrhage and that neuroprotection induced by ATP administration in ICH rats is accompanied by a strong increase in the mBDNF/proBDNF ratio. Here, we also show a significant role of P2X4R-p38-MAPK signalling in the ATP-induced increase in the mBDNF/proBDNF ratio in ICH.

Effects of adenosine triphosphate on methanol-induced experimental optic nerve damage in rats: biochemical and histopathological evaluation

Purpose Acute methanol exposure leads to systemic intoxication and toxic optic neuropathy. In this experimental study, we aimed to determine the protective effects of intravenous administration of ATP in methanol-induced optic neuropathy. Materials and methods A total of 18 male albino Wistar rats weighing between 267 and 282 g were used for the experiment. The animals were divided into three groups as healthy control (HC), methanol (M), and methanol + ATP (M-ATP) groups. Distilled water was given to the healthy control group (n = 6) as the solvent, while 20% methanol was administered orally to the rats in M (n = 6) and M-ATP (n = 6) groups at a dose of 3 g/kg. Four hours after the administration of 20% methanol orally to the M-ATP group, ATP was injected intraperitoneally at a dose of 4 mg/kg. Eight hours after ATP injection, the animals were sacrificed by high-dose (50 mg/kg) thiopental anaesthesia and biochemical and histopathological examinations were performed on the removed optic nerve tissues. Malondialdehyde (MDA), total glutathione (tGSH), total oxidant status (TOS) and total anti-oxidant status (TAS) were analysed with biochemical tests. Results MDA, TOS and OSI were significantly higher and tGSH and TAS levels were significantly lower in methanol administered group compared with the healthy controls or M-ATP group (p: 0.001). There was not any significant difference between healthy controls and M-ATP group regarding the oxidative stress parameters. There was a significant destruction and increase in thickness and astrocyte numbers and edema-vacuolization in methanol administered group compared with the healthy controls or M-ATP group (p: 0.001). Conclusion Intravenous ATP administration had a significant positive effect on the oxidative stress parameters and optic nerve structure in methanol-intoxicated rats. Antioxidant therapies should be considered in future studies as a possible therapy for methanol-induced toxic optic neuropathy.

Hit me with your best shot… to regenerate

Intraneural ATP injection improves axonal recovery following spinal cord injury.

Intraneural Injection of ATP Stimulates Regeneration of Primary Sensory Axons in the Spinal Cord.

Injury to the peripheral axons of sensory neurons strongly enhances the regeneration of their central axons in the spinal cord. It remains unclear on what molecules that initiate such conditioning effect. Because ATP is released extracellularly by nerve and other tissue injury, we hypothesize that injection of ATP into a peripheral nerve might mimic the stimulatory effect of nerve injury on the regenerative state of the primary sensory neurons. We found that a single injection of 6 μl of 150 μm ATP into female rat sciatic nerve quadrupled the number of axons growing into a lesion epicenter in spinal cord after a concomitant dorsal column transection. A second boost ATP injection 1 week after the first one markedly reinforced the stimulatory effect of a single injection. Single ATP injection increased expression of phospho-STAT3 and GAP43, two markers of regenerative activity, in sensory neurons. Double ATP injections sustained the activation of phospho-STAT3 and GAP43, which may account for the marked axonal growth across the lesion epicenter. Similar studies performed on P2X7 or P2Y2 receptor knock-out mice indicate P2Y2 receptors are involved in the activation of STAT3 after ATP injection or conditioning lesion, whereas P2X7 receptors are not. Injection of ATP at 150 μm caused little Wallerian degeneration and behavioral tests showed no significant long-term adverse effects on sciatic nerve functions. The results in this study reveal possible mechanisms underlying the stimulation of regenerative programs and suggest a practical strategy for stimulating axonal regeneration following spinal cord injury.SIGNIFICANCE STATEMENT Injury of peripheral axons of sensory neurons has been known to strongly enhance the regeneration of their central axons in the spinal cord. In this study, we found that injection of ATP into a peripheral nerve can mimic the effect of peripheral nerve injury and significantly increase the number of sensory axons growing across lesion epicenter in the spinal cord. ATP injection increased expression of several markers for regenerative activity in sensory neurons, including phospho-STAT3 and GAP43. ATP injection did not cause significant long-term adverse effects on the functions of the injected nerve. These results may lead to clinically applicable strategies for enhancing neuronal responses that support regeneration of injured axons.

ROBOTIC CATHETER ABLATION OF PERSISTENT ATRIAL FIBRILLATION (RANDOMIZED TRIAL RESULTS)

Aim. Comparison of efficacy and safety of the robotic catheter and manual catheter ablation in management of patients with persistent atrial fibrillation (PsAF). Material and methods . In the study, 80 patients included, with PsAF. They were randomized to groups of manual ablation (MA) and robotic ablation (RA). After ablation, patients were followed up during 1 year every 3 months. Sinus rhythm retention was evaluated with Holter 24-hour ECG monitoring and 12-channel ECG. As efficacy criteria, the absence was taken of registered paroxysms of atrial fibrillation and other tachiarrhythmias lasted 30 sec and more. As primary endpoint, the absence was taken of any atrial tachiarrhythmias (AFib/AFlut) after the ablation procedure during 12 months, with every 3 months ECG monitoring. As secondary endpoints the following were taken: complications rate, duration of procedure and x-ray exposition, rate of recovery of conduction through the ablation line in acute phase (in 30 min post ablation) with intravenous ATP. Results. Mean procedure time and x-rays exposition in MA group was 164±28 min and 45±14 min, respectively. Mean duration of procedure in RA was 200±35 min (p<0,05). However x-ray duration was lower in RA group: 30±12 min, and the time of rentgenoscopy per operator was even lower: 18±6 min (p<0,05) In the MA group, in 9 (25%) patients there was recovery of conduction through the border, with ATP injection at acute stage, and in RA group — in two patients (5%), p<0,05. Total number of adverse events did not differ in groups (p=0,5). Conclusion. RA in patients with PsAF makes in to effectively isolate pulmonary veins ostia during the surgery, and to block the conduction through the borderline. The percentage of major and minor adverse events in acute and chronic period of RA is not higher than that in MA and is 10%. Application of RA makes it to decrease x-ray exposition per operator 2,5 times, and on a patient — by 30%. Training period in RA is 10 operations that is significantly lower than in MA.

Purinergic signalling contributes to chemoreception in the retrotrapezoid nucleus but not the nucleus of the solitary tract or medullary raphe

Several brain regions are thought to function as important sites of chemoreception including the nucleus of the solitary tract (NTS), medullary raphe and retrotrapezoid nucleus (RTN). In the RTN, mechanisms of chemoreception involve direct H(+)-mediated activation of chemosensitive neurons and indirect modulation of chemosensitive neurons by purinergic signalling. Evidence suggests that RTN astrocytes are the source of CO2-evoked ATP release. However, it is not clear whether purinergic signalling also influences CO2/H(+) responsiveness of other putative chemoreceptors. The goals of this study are to determine if CO2/H(+)-sensitive neurons in the NTS and medullary raphe respond to ATP, and whether purinergic signalling in these regions influences CO2 responsiveness in vitro and in vivo. In brain slices, cell-attached recordings of membrane potential show that CO2/H(+)-sensitive NTS neurons are activated by focal ATP application; however, purinergic P2-receptor blockade did not affect their CO2/H(+) responsiveness. CO2/H(+)-sensitive raphe neurons were unaffected by ATP or P2-receptor blockade. In vivo, ATP injection into the NTS increased cardiorespiratory activity; however, injection of a P2-receptor blocker into this region had no effect on baseline breathing or CO2/H(+) responsiveness. Injections of ATP or a P2-receptor blocker into the medullary raphe had no effect on cardiorespiratory activity or the chemoreflex. As a positive control we confirmed that ATP injection into the RTN increased breathing and blood pressure by a P2-receptor-dependent mechanism. These results suggest that purinergic signalling is a unique feature of RTN chemoreception.

Clinical Impact of Adenosine Triphosphate Injection on Arrhythmogenic Superior Vena Cava in the Context of Atrial Fibrillation Ablation

Superior vena cava (SVC) is an infrequent yet an important source of atrial fibrillation. The clinical impact of ATP injection on arrhythmogenic SVC has not been evaluated. A total of 43 patients (59±11 years; men, 32) who underwent ATP test for arrhythmogenic SVC after the electric isolation at either initial procedure or repeat procedure were included. Pulmonary vein antrum isolation was performed at index procedure in all patients. SVC was isolated after identifying the arrhythmogenicity at index and repeat atrial fibrillation ablation procedure in 34 (79.1%) and 9 (20.9%) patients, respectively. Atrial fibrillation originated from the SVC spontaneously and under isoproterenol infusion in 30 (75.0%) patients, and immediately after ATP injection in 10 (25.0%) patients. Tachycardia persistently confined to SVC was recorded after electric isolation in 13 (30.2%) patients. SVC reconnection was provoked by ATP test in 7 of 36 (19.4%) patients at acute phase. At median 4.0 (2.25-7.5) months after SVC isolation, reconnection was observed in 12 of 15 (80.0%) patients at repeat procedure. Among 12 patients with reconnection at baseline, SVC reconnection was provoked by ATP test after reisolation in 1 (8.3%) patient. Among 3 patients without SVC reconnection at baseline, reconnection was provoked by ATP test at chronic phase in 1 patient. Dormant conduction between an arrhythmogenic SVC and the right atrium can be exposed by ATP administration both immediately and late after isolation, potentially facilitating detection and ablation for isolation.

2PT186 ATPショットとcaged-ATPの光分解により開始されるホタル生物発光の時間発展及びそのpH依存性(日本生物物理学会第50回年会(2012年度))

2PT186 ATPショットとcaged-ATPの光分解により開始されるホタル生物発光の時間発展及びそのpH依存性(日本生物物理学会第50回年会(2012年度))

In the trigeminal ganglia, GABAA receptor subunit α6 modulated TMJ nociception in rats

Numerous studies have reported a greater incidence of symptomatic TMJ inflammation/pain in females suggesting gonadal hormones may play a role. Previous studies in our lab showed expression of the GABAA receptor subunit α6 (Gabrα6) was significantly upregulated in the trigeminal ganglion (TG) neurons when comparing rats given high (proestrus) versus low (diestrus) concentrations of estrogen suggesting involvement of the Gabrα6 subunit in TMJ nociception. This increase in Gabrα6 expression was observed in rats with and without TMJ inflammation. The aim of this study was to determine if siRNA knock-down of Gabrα6 expression in the TG affects TMJ nociception. To address this aim, the TG of male Sprague-Dawley rats was bilaterally cannulated and infused with Gabrα6 siRNA, control siRNA or saline. Two days later the rats received bilateral TMJ injection (15 μg) of complete Freund's adjuvant or saline. A behavioral change (i.e. meal duration), phosphorylated ERK (p-ERK) expression in neurons and glia of the TG was used to determine nociception in rats with TMJ inflammation. p-ERK levels and single cell recordings of cells (± 1mM TMJ ATP injection) in the TG and the lamina I/II layers of C1 were completed to assess non-inflammatory TMJ nociception. The results show Gabrα6 siRNA reduced expression in the TG neurons. In the Gabrα6 siRNA/CFA group, meal duration was significantly longer and p-ERK expression was significantly greater as compared to all other CFA injected groups after 48 hours. In the rats without TMJ inflammation, Gabrα6 siRNA resulted in greater p-ERK expression in TG and increased neuronal activity (spikes/s) in the TG and C1 region as compared to rats infused with control siRNA. In conclusion, reduced expression of Gabrα6 increased the nociceptive response consistent with the idea that Gabrα6 in the TG functions in inhibition of TMJ nociception. Supported by NIDCR grants DE016059-01 (LLB) and DE15372 (PRK).

Evaluation of the Efficacy of an Irrigated Catheter as Compared to Non-Irrigated for AF Ablation

Background: Irrigated catheters deliver more adequate radiofrequency energy for creating transmural lesions than conventional catheters for AF ablation. Objective: The aim of this study was to evaluate the efficacy of irrigated catheters as compared to non-irrigated for AF ablation. Methods: A total of 309 consecutive symptomatic AF patients underwent circumferential pulmonary vein isolation (CPVI). They were divided into three groups in a retrospective review; those that a 3.5-mm-irrigated (n=103, Group 1), 4-mm tip (n=100, Group 2) or 8-mm-tip catheter was used (n=106, Group 3). Results: The total radiofrequency energy was significantly greater in Groups 1 and 3 than in Group 2. A simultaneous ipsilateral both PVI occurred significantly more in Group 1 than in Groups 2 or 3. After a successful PVI, transient PV reconnections induced by an ATP injection in right PVs were significantly more decreased in Group 1 than in Group 3. The cumulative freedom from recurrence was significantly more decreased in Groups 1 and 3 than in Group 2 during a follow-up of 11.4±3.1 months (p<0.05). A multivariate logistic regression analysis indicated that using a 4-mm-tip catheter was the only independent predictor of AF recurrence (P=0.045). Conclusions: Irrigated catheters produced more simultaneous ipsilateral PVIs, less acute transient PV reconnections using ATP and less AF recurrence than non-irrigated. The outcomes in acute and chronic phases were better with irrigated catheters.

ATP-mediated protein kinase B Akt/mammalian target of rapamycin mTOR/p70 ribosomal S6 protein p70S6 kinase signaling pathway activation promotes improvement of locomotor function after spinal cord injury in rats

The protein kinase B (Akt)/mammalian target of rapamycin (mTOR)/p70 ribosomal S6 protein kinase (p70S6K) signaling pathway, as a central controller of cell growth, proliferation, survival, and differentiation in response to extracellular signals, growth factors, nutrient availability, energy status of the cell, and stress, has recently gained attention in neuroscience. The effects of this signaling pathway on repair of spinal cord injury (SCI), however, have not been well elucidated. ATP is increasingly recognized as an important regulator of signal transduction pathways, and plays important roles in functional recovery after nervous system injury. In the present study, we examined the ATP-induced changes of the Akt/mTOR/p70S6K signaling pathway in injured spinal cord of adult rats and potential therapeutic effects of this pathway on SCI-induced locomotor dysfunction. SCI was produced by extradural weight-drop using modified Allen's stall with damage energy of 50 g-cm force. The rats were divided into four groups: SCI plus ATP, SCI plus saline, SCI plus ATP and rapamycin, and sham-operated. Using immunostaining studies, Western blot analyses and real-time qualitative RT-PCR analyses, we demonstrated that the Akt/mTOR/p70S6K signaling pathway is present in the injured spinal cord and the expression of its components at the protein and mRNA levels is significantly elevated by exogenous administration of ATP following SCI. We observed the effectiveness of the activated Akt/mTOR/p70S6K signaling pathway in improving locomotor recovery, significantly increasing the expression of nestin, neuronal nuclei (NeuN), neuron specific enolase (NSE), and neurofilament 200 (NF200), and relatively inhibiting excessive reactive astrogliosis after SCI in a rapamycin-sensitive manner. We concluded that ATP injection produced a significant activation of the Akt/mTOR/p70S6K signaling pathway in the injured spinal cord and that enhancement of rapamycin-sensitive signaling produces beneficial effects on SCI-induced motor function defects and repair potential. We suggest that modulation of this protein kinase signaling pathway activity should be considered as a potential therapeutic strategy for SCI.

ATP‐Induced Dormant Pulmonary Veins Originating from the Carina Region After Circumferential Pulmonary Vein Isolation of Atrial Fibrillation

Elimination of transient pulmonary vein recurrences (dormant PVs) induced by an ATP injection and ablation at the PV carina region is an effective strategy for atrial fibrillation (AF) ablation. The relationship between dormant PVs and the PV carina region has not been evaluated. A total of 212 consecutive symptomatic AF patients underwent circumferential PV electrical isolation (CPVEI) with a double lasso technique. They were divided into 2 groups in a retrospective review; Group 1: those given an ATP injection during an intravenous isoproterenol infusion after the CPVEI (n = 106), and Group 2: those in which it was not given after the CPVEI (n = 106). Radiofrequency energy was applied at the earliest dormant PV activation site identified using a Lasso catheter on the CPVEI line and then PV carina region if it was ineffective. After a successful PVEI, 54 patients (51%) in Group 1 had PV reconnections during an ATP injection. Acute PVEI sites were observed on the carina region within the CPVEI line in the right PVs (16%) and left PVs (10%). Dormant PVs were reisolated at the carina region in the right PVs (23%) and left PVs (26%). The distribution of the dormant PV sites, except for the RIPV, significantly differed from that of the acute PVEI sites (P < 0.05). Further, AF recurred significantly in the Group 2 patients as compared to those in Group 1 during 16 +/- 6.1 months of follow-up (P < 0.05). PV carina region origins may partly be responsible for an acute PVEI and potential recurrences.