Safety and Efficacy of Traditional Heart Failure Therapies in Patients With Cardiac Amyloidosis and Heart Failure.

Randomized controlled trials have demonstrated mortality benefits for several medication classes in patients with heart failure (HF), especially with reduced ejection fraction (EF). However, the benefit of these traditional HF therapies in patients with HF from cardiac amyloidosis is unclear. our study aimed to evaluate the safety and efficacy of traditional HF therapies in patients with cardiac amyloidosis and HF with reduced EF or HF with mid-range EF (HFmrEF). We conducted a single-center retrospective study. Patients were included if they were diagnosed with cardiac amyloidosis and HF with reduced EF or HF with mid-range EF between January 2012 and 2022. The primary outcomes of interest were medication use patterns (for ß blockers [BB], angiotensin-converting enzyme inhibitors [ACEI], angiotensin receptor blockers [ARBs], angiotensin receptor neprilysin inhibitors [ARNI], and mineralocorticoid receptor antagonists [MRAs]); potential medication side effects (symptomatic bradycardia, fatigue, hypotension, lightheadedness, and syncope); hospitalization; and death. The associations of BB, ACEI/ARB/ARNI, and MRA use with clinical outcomes were evaluated using Kaplan-Meier and Cox proportional hazards regression. A total of 82 patients met study criteria. At time of cardiac amyloidosis diagnosis, 63.4% were on a BB, 51.2% were on an ACEI/ARB/ARNI, and 43.9% were on an MRA. At last follow-up, 51.2% were on a BB, 35.4% were on an ACEI/ARB/ARNI, and 43.9% were on an MRA. There were no statistically significant differences in rates of potential medication side effects in patients on the medication class compared with those who were not. There was no association with hospitalization or mortality for baseline or follow-up BB, ACEI/ARB/ARNI, or MRA use. In conclusion, BBs, ACEI/ARB/ARNIs, and MRAs may be safely used in this population. However, their use does not appear to improve mortality or hospitalization.

Holistic approach to drug therapy in a patient with heart failure.

Heart failure (HF) is a growing global public health problem affecting at least 26 million people worldwide. The evidence-based landscape for HF treatment has changed at a rapid rate over the last 30 years. International guidelines for the management of HF now recommend the use of four pillars in all patients with reduced ejection fraction: angiotensin receptor neprilysin inhibitors or ACE inhibitors, beta blockers, mineralocorticoid receptor antagonists and sodium-glucose co-transporter-2 inhibitors. Beyond the main four pillar therapies, numerous further pharmacological treatments are also available in specific patient subtypes. These armouries of drug therapy are impressive, but where does this leave us with individualised and patient-centred care? This paper reviews the common considerations needed to provide a holistic, tailored and individual approach to drug therapy in a patient with HF with reduced ejection fraction, including shared decision making, initiating and sequencing of HF pharmacotherapy, drug-related considerations, polypharmacy and adherence.

Latest Knowledge on the Role of Vitamin D in Hypertension.

Hypertension is the third leading cause of the global disease burden, and while populations live longer, adopt more sedentary lifestyles, and become less economically concerned, the prevalence of hypertension is expected to increase. Pathologically elevated blood pressure (BP) is the strongest risk factor for cardiovascular disease (CVD) and related disability, thus making it imperative to treat this disease. Effective standard pharmacological treatments, i.e., diuretics, angiotensin converting enzyme (ACE) inhibitors, angiotensin receptor blocker (ARBs), beta-adrenergic receptor blockers (BARBs), and calcium channel blockers (CCBs), are available. Vitamin D (vitD) is known best for its role in bone and mineral homeostasis. Studies with vitamin D receptor (VDR) knockout mice show an increased renin-angiotensin-aldosterone system (RAAS) activity and increased hypertension, suggesting a key role for vitD as a potential antihypertensive agent. Similar studies in humans displayed ambiguous and mixed results. No direct antihypertensive effect was shown, nor a significant impact on the human RAAS. Interestingly, human studies supplementing vitD with other antihypertensive agents reported more promising results. VitD is considered a safe supplement, proposing its great potential as antihypertensive supplement. The aim of this review is to examine the current knowledge about vitD and its role in the treatment of hypertension.

Maoto, a traditional Japanese medicine, controls acute systemic inflammation induced by polyI:C administration through noradrenergic function.

Maoto, a traditional Japanese medicine (Kampo), is widely used to treat upper respiratory tract infections, including influenza virus infection. Although maoto is known to inhibit pro-inflammatory responses in a rodent model of acute inflammation, its underlying mechanism remains to be determined. In this study, we investigated the involvement of immune responses and noradrenergic function in the inhibitory action of maoto. In a mouse model of polyI:C-induced acute inflammation, maoto was administered orally in conjunction with intraperitoneal injection of PolyI:C (6 mg/kg), and blood was collected after 2 h for measurement of plasma cytokines by ELISA. Maoto significantly decreased PolyI:C-induced TNF-α levels and increased IL-10 production. Neither pretreatment with IL-10 neutralizing antibodies nor T-cell deficiency using nude mice modified the inhibitory effect of maoto, indicating that the anti-inflammatory effects of maoto are independent of IL-10 and T cells. Furthermore, the inhibitory effects of maoto on PolyI:C-induced TNF-α production were not observed in ex vivo splenocytes, suggesting that maoto does not act directly on inflammatory cells. Lastly, pretreatment with a ß-adrenergic receptor antagonist partially cancelled the anti-inflammatory effects of maoto. Collectively, these results suggest that maoto mediates its anti-inflammatory effects via ß-adrenergic receptors in vivo.

Comparing thermal stress reduction strategies that influence MDSC accumulation in tumor bearing mice.

Myeloid derived suppressor cells (MDSCs) are a diverse collection of immune cells that suppress anti-tumor immune responses. Decreasing MDSCs accumulation in the tumor microenvironment could improve the anti-tumor immune response and improve immunotherapy. Here, we examine the impact of physiologically relevant thermal treatments on the accumulation of MDSCs in tumors in mice. We found that different temperature-based protocols, including 1) weekly whole-body hyperthermia, 2) housing mice at their thermoneutral temperature (TT, ~30 °C), and 3) housing mice at a subthermoneutral temperature (ST,~22 °C) while providing a localized heat source, each resulted in a reduction in MDSC accumulation and improved tumor growth control compared to control mice housed at ST, which is the standard, mandated housing temperature for laboratory mice. Additionally, we found that low dose ß-adrenergic receptor blocker (propranolol) therapy reduced MDSC accumulation and improved tumor growth control to a similar degree as the models that relieved cold stress. These results show that thermal treatments can decrease MDSC accumulation and tumor growth comparable to propranolol therapy.

Transforming Growth Factor-ß and the Renin-Angiotensin System in Syndromic Thoracic Aortic Aneurysms: Implications for Treatment.

Thoracic aortic aneurysms (TAAs) are permanent pathological dilatations of the thoracic aorta, which can lead to life-threatening complications, such as aortic dissection and rupture. TAAs frequently occur in a syndromic form in individuals with an underlying genetic predisposition, such as Marfan syndrome (MFS) and Loeys-Dietz syndrome (LDS). Increasing evidence supports an important role for transforming growth factor-ß (TGF-ß) and the renin-angiotensin system (RAS) in TAA pathology. Eventually, most patients with syndromic TAAs require surgical intervention, as the ability of present medical treatment to attenuate aneurysm growth is limited. Therefore, more effective medical treatment options are urgently needed. Numerous clinical trials investigated the therapeutic potential of angiotensin receptor blockers (ARBs) and ß-blockers in patients suffering from syndromic TAAs. This review highlights the contribution of TGF-ß signaling, RAS, and impaired mechanosensing abilities of aortic VSMCs in TAA formation. Furthermore, it critically discusses the most recent clinical evidence regarding the possible therapeutic benefit of ARBs and ß-blockers in syndromic TAA patients and provides future research perspectives and therapeutic implications.

Aqueous extract of oakmoss produces antihypertensive activity in L-NAME-induced hypertensive rats through sGC-cGMP pathway.

BACKGROUND: Lichens are a symbiotic association of a fungus with a green alga or cyanobacterium. They are widely used in traditional medicine as a treatment against skin disorders, diabetes and hypertension. THE AIM OF THE STUDY: The goal of this paper was to assess the possible antihypertensive and vasorelaxant capacity of the aqueous extract of a lichen species called Oakmoss or Evernia prunastri (L.). MATERIAL AND METHODS: In the present study, the aqueous extract of Oakmoss was prepared, its antihypertensive activity was examined in N(ω)-nitro-L-arginine methyl ester (L-NAME)-induced hypertensive rats, and its vasorelaxant ability was performed in rat isolated thoracic aorta. RESULTS: The results proved that Oakmoss reduced the systolic, diastolic, mean arterial blood pressure, and heart rate in hypertensive rats but not in normotensive rats. Besides, the data showed that Oakmoss exerts its antihypertensive effect through vasorelaxant ability. CONCLUSION: The present study presents the favorable action of Oakmoss as an antihypertensive agent.

Effects of Anisodine Hydrobromide on the Cardiovascular and Respiratory Functions in Conscious Dogs.

PURPOSE: Anisodine hydrobromide (Ani) is isolated from the medicinal plant Anisodus tanguticus (Maxim.) Pascher for clinical use. Although considerable research regarding Ani has been reported, the safety profiles of Ani are currently unknown. This study investigated the cardiorespiratory effects of Ani in conscious dogs to provide clinicians a detailed safety profile of Ani on the cardiorespiratory system. MATERIALS AND METHODS: Using the Latin square design, the study was divided into six phases, where in each phase, six telemetered beagle dogs received one dose of normal saline or sotalol hydrochloride or Ani (0.1, 0.4, 1.6, or 6.4 mg/kg). Electrocardiogram, blood pressure (BP) and respiratory parameters were collected before and after administration for 24 hours. Statistical comparisons were performed at scheduled time-points. RESULTS: The heart rate was significantly increased, PR and QTCV intervals were significantly shortened in Ani 0.4, 1.6, 6.4 mg/kg treatment group after drug administration. Compared with the saline group, a significant increase in heart rate and shortening of PR, QTCV intervals were observed in the Ani 1.6, 6.4 mg/kg treatment groups from 5 min to 4 h time-points. Diastolic and mean BP were significantly increased in Ani 1.6, 6.4 mg/kg from 1 h to 2 h time-points compared to those of the saline control. Accelerated breathing was observed in the first 20 min after Ani 0.4, 1.6, and 6.4 mg/kg treatment, although not statistically significant. Furthermore, no significant differences were observed in any of the corresponding indexes of Ani 0.1 mg/kg treatment group at different time-points compared to those of the saline group. CONCLUSION: Ani may have adverse effects on the cardio-respiratory systems of dogs at doses above 0.4 mg/kg, whereas Ani 0.1 mg/kg was devoid of potentially deleterious effects on cardiorespiratory function.

Beta-Blockers and Berberine: A Possible Dual Approach to Contrast Neuroblastoma Growth and Progression.

The use of nutraceuticals during cancer treatment is a long-lasting debate. Berberine (BBR) is an isoquinoline quaternary alkaloid extracted from a variety of medicinal plants. BBR has been shown to have therapeutic effects in different pathologies, particularly in cancer, where it affects pathways involved in tumor progression. In neuroblastoma, the most common extracranial childhood solid tumor, BBR, reduces tumor growth by regulating both stemness and differentiation features and by inducing apoptosis. At the same time, the inhibition of ß-adrenergic signaling leads to a reduction in growth and increase of differentiation of neuroblastoma. In this review, we summarize the possible beneficial effects of BBR in counteracting tumor growth and progression in various types of cancer and, in particular, in neuroblastoma. However, BBR administration, besides its numerous beneficial effects, presents a few side effects due to inhibition of MAO A enzyme in neuroblastoma cells. Therefore, herein, we proposed a novel therapeutic strategy to overcome side effects of BBR administration consisting of concomitant administration of BBR together with ß-blockers in neuroblastoma.

Cardiac sympathetic activation circumvents high-dose beta blocker therapy in part through release of neuropeptide Y.

The sympathetic nervous system plays an important role in the occurrence of ventricular tachycardia (VT). Many patients, however, experience VT despite maximal doses of beta blocker therapy, possibly due to the effects of sympathetic cotransmitters such as neuropeptide Y (NPY). The purpose of this study was to determine, in a porcine model, whether propranolol at doses higher than clinically recommended could block ventricular electrophysiological effects of sympathoexcitation via stellate ganglia stimulation, and if any residual effects are mediated by NPY. Greater release of cardiac NPY was observed at higher sympathetic stimulation frequencies (10 and 20 vs. 4 Hz). Despite treatment with even higher doses of propranolol (1.0 mg/kg), electrophysiological effects of sympathetic stimulation remained, with residual shortening of activation recovery interval (ARI), a surrogate of action potential duration (APD). Adjuvant treatment with the NPY Y1 receptor antagonist BIBO 3304, however, reduced these electrophysiological effects while augmenting inotropy. These data demonstrate that high-dose beta blocker therapy is insufficient to block electrophysiological effects of sympathoexcitation, and a portion of these electrical effects in vivo are mediated by NPY. Y1 receptor blockade may represent a promising adjuvant therapy to beta-adrenergic receptor blockade.

Self-Reported Omega-3 Supplement Use Moderates the Association between Age and Exercising Cerebral Blood Flow Velocity in Older Adults.

Cerebral blood flow (CBF) decreases across the lifespan, and chronic conditions such as dementia and stroke accelerate this decline. Impaired CBF results in reduced delivery of oxygen and nutrients, which can damage the brain over time. Thus, there is a need to identify lifestyle interventions, including diet and exercise, to maintain CBF with aging and in the presence of chronic disease. In the present study, we used transcranial Doppler ultrasound to record middle cerebral artery velocity (MCAv), a surrogate measure of CBF, during moderate-intensity exercise in sedentary, cognitively normal older adults (n = 90). A multiple linear regression model (F(4, 85) = 3.21, p = 0.02) showed that self-reported omega-3 supplement use significantly moderated the association between age and mean exercising MCAv in these individuals (p = 0.01). Older age was associated with lower exercising MCAv in the group not taking omega-3 supplements, while exercising MCAv showed no decline with increasing age in the group who reported omega-3 supplement use. These findings suggest omega-3 supplementation may have an important role in the preservation of CBF with aging.

Persea Americana Seeds Cause Ileal Smooth Muscle Relaxation Via Stimulation of α-1 Adrenoceptors.

The effect of methanol extract of P. americana seeds on isolated ileal smooth muscle was studied for isometric response using 10 adult rabbits of both sexes. Reactivity and agonist-antagonist responses of rabbit ileum to the extract were determined in this study. The affinity, effective concentration to give 50% response (EC50) and maximum response were calculated from the concentration response curves (CRC) obtained. The result for the reactivity study showed the seed extract of P. americana caused concentration dependent relaxation of isolated rabbit ileum with threshold responses at concentration of 1×10-9 mg/ml and 120 mg/ml respectively. The extract-antagonist study showed an upward and right shift in CRC in the presence of phenoxybenzamine, a non-selective adrenergic antagonist, with the EC50 increased from 5.01 mg/ml to 12.59 mg/ml and affinity decreased from 0.20 to 0.08. Extract-antagonist study also showed a right and upward shift in the CRC with a greater magnitude in the presence of prazosin, an α1-adrenergic antagonist, with EC50 increased from 0.32 mg/ml to 25.12 mg/ml and a consequential decrease in the affinity from 3.13 to 0.04. In the presence of propranolol, a ß-adrenergic antagonist, a downward and left shift in the CRC was observed with the EC50 and PA2 remaining constant at 0.1 mg/ml and 10 respectively. P. americana concentration-dependently reduced or inhibited gastric motility, increasing transit time which is important for food absorption, thus a pro-nutritive and antispasmodic effect. The interaction with α1-adrenoceptors is beneficially in heart failure management. The plant can be developed as a drug candidate for management of hypertension.

Acupuncture versus propranolol in migraine prophylaxis: an indirect treatment comparison meta-analysis.

BACKGROUND: Propranolol is recommended as first-line treatment for preventing migraine attacks; acupuncture has not been compared with propranolol in a head-to-head trial. OBJECTIVE: To compare acupuncture with propranolol using indirect treatment comparison meta-analysis. METHOD: We searched MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL). Randomized controlled trials comparing acupuncture or propranolol with sham acupuncture, placebo, waiting-list control or usual care were included. We extracted information from the included trials using a standardized extraction form. The primary outcome was migraine episodes. The secondary outcomes included migraine days, migraine frequency, and adverse events. RESULTS: We included 19 RCTs (n = 3656) after screening 1078 articles. The analysis showed that acupuncture had a significant advantage over propranolol in reducing migraine episodes over a 4-week period (SMD - 0.74, 95% CI - 1.04 to - 0.44). Acupuncture also had a significant advantage over waiting-list control in decreasing migraine frequency (SMD - 1.57, 95% CI - 2.08 to - 1.06). Acupuncture caused fewer adverse events than propranolol (RR 0.82, 95% CI 0.11-5.94). CONCLUSIONS: Acupuncture had a better effect than propranolol in reducing migraine episodes in indirect comparison. The result should be confirmed in subsequent head-to-head studies. Registration: PROSPERO CRD42018108585.

Comparative effect of Beta blocker-Atenolol and Murraya koenigii (L.) spreng (Curry leaves) on cardiac enzyme (CK-MB) level in male albino rats.

Murraya koenigii (L.) spreng (curry leaves) have traditionally been used for its various medicinal properties. The current study was conducted to assess the comparative effect of Murraya koenigii (L.) spreng (curry leaves) and market available beta blocker drug Atenolol on cardiac enzyme (CK-MB) level in male albino rats. Out of total 26 locally bred male Albino Wistar rats (180 to 200gm weight) two rats were treated with only voltral for dose adjustment. Remaining 24 rats were randomly categorized into following 1 control (C) group and 3 experimental groups Model (M), Test 1 (T1) and Test 2 (T2) containing 6 rats in each group. Rats in C group were orally fed by 0.9% saline solution while rats of M and both test groups T1 and T2 were orally treated with voltral tablet (30mg /kg body weight) for three weeks to increase the level of CK-MB heart enzyme. After voltral treatment rats in test group T1 were treated orally with Atenolol (30 mg/kg body weight) and T2 with Murraya koenigii (L.) spreng (curry leaves) extract (180 mg/kg body weight) for last three weeks. Results show that rats treated with Atenolol showed a decrease in level of heart enzyme as compare to M group, while Murraya koenigii (L.) spreng treated rats group T2 showed more significant decrease of heart enzyme (CK-MB) level as compared to M and T1 groups with significantly improved behavioral activity including increased locomotor activity, short-term memory and reduction in depression. These results demonstrate that natural herbal treatment by curry leaves extract play an effective role in lowering the cardiac enzyme (CK-MB) level to its normal range which helps reducing the risk of CVD and CHD.

Propranolol prevents cerebral blood flow changes and pain-related behaviors in migraine model mice.

Propranolol, a ß-adrenergic receptor blocker, is one of the most commonly used prophylactic drugs for migraines. Cortical spreading depression (CSD) is the propagation wave of neuronal excitation along with cerebral blood flow (CBF) changes over the cerebral cortex and has been implicated in the pathological process of migraine auras and its pain response. However, the effect of propranolol on CSD-related CBF changes and behavioral responses remains poorly understood. In this study, we measured CSD-related CBF responses using a micro-device with a green light emitting diode (LED) and micro-complementary-metal-oxide-semiconductor (CMOS) image sensor and evaluated pain-related reduced locomotor activity in mice. An injection of KCl into the visual cortex led to CSD-related CBF changes; however, propranolol prevented the increase in CBF as well as delayed the propagation velocity in KCl-induced CSD. Furthermore, an injection of KCl reduced locomotor activity and induced freezing behavior in awake and freely moving mice, which were prevented by propranolol treatment. These results suggest that the modulation of CSD-related CBF responses by the blockade of ß-adrenergic receptor contributes to its prophylactic effects on migraines.

Discovery of ß-Adrenergic Receptors Blocker-Carbonic Anhydrase Inhibitor Hybrids for Multitargeted Antiglaucoma Therapy.

The combination of a ß-adrenergic receptors (AR) blocker and a carbonic anhydrase (CA, EC 4.2.1.1) inhibitor in eye drops formulations is one of the most clinically used treatment for glaucoma. A novel approach consisting of single-molecule, multitargeted compounds for the treatment of glaucoma is proposed here by designing compounds which concomitantly interact with the ß-adrenergic and CA targets. Most derivatives of the two series of benzenesulfonamides incorporating 2-hydroxypropylamine moieties reported here exhibited striking efficacy against the target hCA II and XII, whereas a subset of compounds also showed significant modulation of ß1- and ß2-ARs. X-ray crystallography studies provided rationale for the observed hCA inhibition. The best dual-agents decreased IOP more effectively than clinically used dorzolamide, timolol, and the combination of them in an animal model of glaucoma. The reported evidence supports the proof-of-concept of ß-ARs blocker-CAI hybrids for antiglaucoma therapy with an innovative mechanism of action.

Divergent profile between hypothalamic and plasmatic aminopeptidase activities in WKY and SHR. Influence of beta-adrenergic blockade.

AIMS: Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR) differ in their renin-angiotensin system function and sympathetic tone. The metabolism of angiotensins and vasopressin depends on the action of certain aminopeptidases whose activity may be influenced by the autonomic nervous system. Their regulation may differ between WKY and SHR in hypothalamus and plasma according to the sympathetic tone. We analyzed aminopeptidases responsible for the hydrolysis of certain angiotensins, vasopressin, cholecystokinin or enkephalins in hypothalamus and plasma of WKY and SHR in untreated controls rats and under beta-adrenoceptor blockade. Systolic blood pressure, food intake, water intake and diuresis were measured as parameters modulated by the autonomic nervous system and the above mentioned peptides. MAIN METHODS: Glutamyl-, aspartyl-, cystinyl- and alanyl-aminopeptidase activities were analyzed fluorimetrically in plasma and hypothalamus of control and propranolol-treated (100mg/kg/day administered in drinking water for 1month) WKY and SHR, using arylamide derivatives as substrates. KEY FINDINGS: An opposite response of aminopeptidases to propranolol treatment between plasma and hypothalamus was observed in either WKY and SHR. Furthermore, the behavior of aminopeptidases was inversed between WKY and SHR either in hypothalamus and plasma: while the activity increased in hypothalamus and decreased in plasma of WKY, it decreased in hypothalamus and increased in plasma of SHR. SIGNIFICANCE: These results revealed an inverse response of aminopeptidases between hypothalamus and plasma and also an opposite behavior of these enzymes between WKY and SHR in hypothalamus and plasma. These observations support the involvement of the sympathetic system in the modulation of aminopeptidase activities.

A Combination of Dexmedetomidine and Lidocaine Is a Cardiovascularly Safe Dental Local Anesthetic for Hypertensive Rats Treated With a Nonselective ß-Adrenergic Antagonist.

Hypertensive patients receiving nonselective ß-adrenergic antagonists are vulnerable to hypertension and bradycardia when injected with dental local anesthetic formulations containing epinephrine. Dexmedetomidine (DEX), an α2-adrenergic agonist, has been reported to prolong and enhance the local anesthetic effects of lidocaine. The cardiovascular effects of the DEX-lidocaine combination have not yet been investigated in the presence of nonselective ß-adrenergic antagonists. Therefore, we assessed the cardiovascular effects of the DEX-lidocaine combination in spontaneously hypertensive rats (SHR) treated with a nonselective ß-adrenergic antagonist (propranolol). We injected propranolol-treated rats with various concentrations of DEX alone, 100 µg/kg epinephrine alone, or 5 µg/kg DEX combined with 2% lidocaine and measured their blood pressure (BP) and heart rates (HR) to assess the cardiovascular effects. The BP of propranolol-treated SHR was significantly increased by treatment with 100 µg/kg epinephrine alone. The BP and HR of propranolol-treated SHR were not significantly changed by treatment with low concentrations of DEX, but they were significantly decreased by treatment with a high concentration of DEX (50 µg/kg). Moreover, there was no significant difference in the BP and HR of propranolol-treated SHR after the injection of a combination of 5 µg/kg DEX and 2% lidocaine. Thus, the DEX-lidocaine combination may be an acceptable addition to dental local anesthetic solutions from a cardiovascular standpoint for hypertensive patients receiving nonselective ß-adrenergic antagonists.

The α2A -adrenoceptor suppresses excitatory synaptic transmission to both excitatory and inhibitory neurons in layer 4 barrel cortex.

KEY POINTS: The effects of noradrenaline on excitatory synaptic transmission to regular spiking (excitatory) cells as well as regular spiking non-pyramidal and fast spiking (both inhibitory) cells in cortical layer 4 were studied in thalamocortical slice preparations, focusing on vertical input from thalamus and layer 2/3 in the mouse barrel cortex. Excitatory synaptic responses were suppressed by noradrenaline. However, currents induced by iontophoretically applied glutamate were not suppressed. Further, paired pulse ratio and coefficient of variation analysis indicated the site of action was presynaptic. Pharmacological studies indicated that the suppression was mediated by the α2- adrenoceptor. Consistent with this, involvement of α2A -adrenoceptor activation in the synaptic suppression in excitatory and inhibitory cells was confirmed by the use of α2A -adrenoceptor knockout mice. ABSTRACT: The mammalian neocortex is widely innervated by noradrenergic (NA) fibres from the locus coeruleus. To determine the effects of NA on vertical synaptic inputs to layer 4 (L4) cells from the ventrobasal thalamus and layer 2/3 (L2/3), thalamocortical slices were prepared and whole-cell recordings were made from L4 cells. Excitatory synaptic responses were evoked by electrical stimulation of the thalamus or L2/3 immediately above. Recorded cells were identified as regular spiking, regular spiking non-pyramidal or fast spiking cells through their firing patterns in response to current injections. NA suppressed (∼50% of control) excitatory vertical inputs to all cell types in a dose-dependent manner. The presynaptic site of action of NA was suggested by three independent studies. First, responses caused by iontophoretically applied glutamate were not suppressed by NA. Second, the paired pulse ratio was increased during NA suppression. Finally, a coefficient of variation (CV) analysis was performed and the resultant diagonal alignment of the ratio of CV-2 plotted against the ratio of the amplitude of postsynaptic responses suggests a presynaptic mechanism for the suppression. Experiments with phenylephrine (an α1 -agonist), prazosin (an α1 -antagonist), yohimbine (an α2 -antagonist) and propranolol (a ß-antagonist) indicated that suppression was mediated by the α2 -adrenoceptor. To determine whether the α2A -adrenoceptor subtype was involved, α2A -adrenoceptor knockout mice were used. NA failed to suppress EPSCs in all cell types, suggesting an involvement of the α2A -adrenoceptor. Altogether, we concluded that NA suppresses vertical excitatory synaptic connections in L4 excitatory and inhibitory cells through the presynaptic α2A -adrenoceptor.

Effect of hyperbaric oxygen therapy on blood pressure in patients undergoing treatment.

INTRODUCTION: Hyperbaric oxygen (HBO2) therapy is generally safe and well tolerated. However, known side effects do exist. Elevation in the blood pressure of patients undergoing HBO2 therapy is a less defined potential side effect. We sought to better quantify effects of HBO2 on blood pressure (BP) in patients undergoing HBO2. METHODS: A retrospective chart review was performed on quality assurance data captured on all patients undergoing HBO2 between March 2012 and October 2015 at a large tertiary referral university hospital hyperbaric center. RESULTS: We identified 155 patients who received 3,147 hyperbaric oxygen treatments. For all treatments there was an overall increase in the median systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) following treatment. No statistically significant difference was found when comparing patients with and without hypertension. Calcium channel blockers (CCB) and beta-blockers (BB) were found to have an agonizing effect while ACE inhibitors (ACEI) were found to have a protective effect. The change in SBP was less with each additional treatment in patients undergoing more than one treatment. DISCUSSION: The current study demonstrates that absolute rises in blood pressure do occur as a result of HBO2 therapy. However, the extent of this effect is not large. BB and CCB had agonizing effects while ACEI had a protective effect. Finally, there was a protective effect with more treatments.