Search results for "block"

Activity-dependent endogenous taurine release facilitates excitatory neurotransmission in the neocortical marginal zone of neonatal rats.

2014

In the developing cerebral cortex, the marginal zone (MZ), consisting of early-generated neurons such as Cajal-Retzius cells, plays an important role in cell migration and lamination. There is accumulating evidence of widespread excitatory neurotransmission mediated by γ-aminobutyric acid (GABA) in the MZ. Cajal-Retzius cells express not only GABAA receptors but also α2/β subunits of glycine receptors, and exhibit glycine receptor-mediated depolarization due to high [Cl(-)]i. However, the physiological roles of glycine receptors and their endogenous agonists during neurotransmission in the MZ are yet to be elucidated. To address this question, we performed optical imaging from the MZ using …

Video-assisted two-stage basilic vein transposition for creation of brachio-basilic arteriovenous fistulae

2012

We report our experience in a mixed minimally-in- vasive technique for the two-stage transposition of basilic vein on a small series of eight patients. The operative tech- nique consisted of a modified endoscopic (1) approach for the two-stage transposition (2). The intervention was performed under Brachial Plexus Block (3).

Corticotropin-Releasing Hormone-Mediated Induction of Intracellular Signaling Pathways and Brain-Derived Neurotrophic Factor Expression Is Inhibited …

2005

CRH receptor (CRHR) 1 and the cannabinoid receptor 1 (CB1) are both G protein-coupled receptors. Activation of CRHR1 leadstoincreasesincAMPproductionandphosphorylationof the transcription factor cAMP response element-binding protein (CREB). In contrast, CB1 is negatively coupled to the cAMP signaling cascade. In this study, we analyzed a putative interaction between these two systems focusing on the regulation of the expression of brain-derived neurotrophic factor (BDNF), a CREB-regulated gene. In situ hybridization revealed coexpression of CRHR1 and CB1 receptors in the granular layer of the cerebellum. Therefore, we analyzed the effects of CRH and the CB1 agonist WIN-55,212-2 on BDNF expr…

The acute myotoxic effects of bupivacaine and ropivacaine after continuous peripheral nerve blockades.

2003

Bupivacaine causes muscle damage. However, the myotoxic potency of ropivacaine is still unexplored. Therefore, we performed this study to compare the effects of bupivacaine and ropivacaine on skeletal muscle tissue in equipotent concentrations. Femoral nerve catheters were inserted into anesthetized minipigs, and 20 mL of either bupivacaine (5 mg/mL) or ropivacaine (7.5 mg/mL) was injected. Subsequently, bupivacaine (2.5 mg/mL) and ropivacaine (3.75 mg/mL) were continuously infused over 6 h. Control animals were treated with corresponding volumes of normal saline. Finally, muscle samples were dissected at injection sites. After processing and staining, histological patterns of muscle damage…

Ultrasound observation of tissue fluid infiltration causing stridor in a woman undergoing shoulder arthroscopy

2012

Respiratory stridor developed rapidly during an interscalene brachial plexus block for shoulder arthroscopy in an obese woman. Extensive cervicothoracic edema due to tissue diffusion of the arthroscopic fluid was suspected. The outcome of patient after conservative management was satisfactory. We give a brief review of how this complication develops, the ultrasound findings, and briefly discuss similar cases.

Effectiveness of beta-blocker in primary prevention of variceal bleeding in patients with cirrhosis: A prospective evaluation by hepatic venous press…

2014

Differential effects of potassium channel blockers on neurohypophysial release of oxytocin and vasopressin. Evidence for frequency-dependent interact…

1988

Isolated rat neurohypophyses were fixed by their stalks to a platinum wire electrode and superfused with Krebs-HEPES solution. Vasopressin and oxytocin released into the medium were determined by specific radioimmunoassays. Hormone secretion was increased by electrical stimulation of the pituitary stalk at different frequencies. The effects of several potassium channel blockers, tetraethylammonium (TEA) ions, 4-aminopyridine (4-AP) and 3,4-diaminopyridine (3,4-DAP) were tested. The release of vasopressin and oxytocin evoked by electrical stimulation with 900 pulses at 15 Hz (about 900 and 1,000 μU, respectively) was about 10 times higher than that evoked by 900 pulses at 3 Hz. Both 10 and 3…

Oral Propranolol for Circumscribed Choroidal Hemangioma

2011

Introduction: Several therapeutic approaches have been developed to treat choroidal hemangioma. However, all these therapies are associated with a potential risk of damaging the overlying retina. Case Report: We report a case of circumscribed choroidal hemangioma (CCH) in a 59-year-old man refractory to laser treatment. Visual acuity was 20/200 and a serous macular detachment was present. The CCH was treated with oral propanolol, whereupon visual acuity improved to 20/20 and the macular detachment resolved without systemic or local adverse effects. Discussion: Propanolol is a β-blocker commonly used in cardiology that may induce endothelium vasoconstriction and inhibit endothelial prolifera…

Selected peptides targeted to the NMDA receptor channel protect neurons from excitotoxic death

1998

Excitotoxic neuronal death, associated with neurodegeneration and stroke, is triggered primarily by massive Ca2+ influx arising from overactivation of glutamate receptor channels of the N-methyl-D-aspartate (NMDA) subtype. To search for channel blockers, synthetic combinatorial libraries were assayed for block of agonist-evoked currents by the human NR1-NR2A NMDA receptor subunits expressed in amphibian oocytes. A set of arginine-rich hexapeptides selectively blocked the NMDA receptor channel with IC50 approximately 100 nM, a potency similar to clinically tolerated blockers such as memantine, and only marginally blocked on non-NMDA glutamate receptors. These peptides prevent neuronal cell d…

Studies using pharmacological blockade of muscle afferents provide new insights into the neurophysiology of perceived exertion

2016

The increase in blood pressure observed during physical activities is exaggerated in patients with hypertension, exposing them to a higher cardiovascular risk.Neural signals from the skeletal muscles appear to be overactive, resulting in this abnormal response in hypertensive patients.In the present study, we tested whether the attenuation of these neural signals in hypertensive patients could normalize their abnormal increase in blood pressure during physical activity.Attenuation of the neural signals from the leg muscles with intrathecal fentanyl injection reduced the blood pressure of hypertensive men during cycling exercise to a level comparable to that of normotensive men.Skeletal musc…