Functional hyperemia in striated muscle is reduced following blockade of ATP-sensitive potassium channels

1996 ◽  
Vol 270 (5) ◽  
pp. H1649-H1654 ◽  
Author(s):  
Y. Saito ◽  
M. McKay ◽  
A. Eraslan ◽  
R. L. Hester
Keyword(s):  
Potassium Channels ◽  
Topical Application ◽  
Muscle Stimulation ◽  
Functional Hyperemia ◽  
Cremaster Muscle ◽  
Third Order ◽  
First Order ◽  
The Third ◽  
Arteriolar Diameter

This study was designed to determine the role of ATP-sensitive potassium channels in the control of the arteriolar diameter during functional hyperemia. The hamster cremaster muscle was prepared for in vivo microscopy and stimulated electrically for 1 min before and after topical application of 10 microM glibenclamide to block ATP-sensitive potassium channels. Glibenclamide treatment resulted in a small, though not significant, decrease in resting arteriolar diameter (P > 0.05). Glibenclamide almost completely inhibited the vasodilation of the first-order and the third-order arterioles in response to topical application of 1 microM cromakalim (P < 0.05). During muscle stimulation, the first-order arterioles dilated from 69 +/- 3 to 89 +/- 3 microns (n = 7), and the third-order arterioles dilated from 16 +/- 1 to 35 +/- 2 microns (n = 7). In this set of experiments glibenclamide treatment resulted in a significant decrease (approximately 4 microns) in the resting diameters of the first-order arterioles, but had no significant effect on the resting diameter of third-order arterioles. Glibenclamide treatment significantly attenuated the vasodilation associated with muscle contraction to 72 +/- 3 and to 21 +/- 3 microns, respectively (P < 0.05). These results suggests that ATP-sensitive potassium channels are an important mediator in the vasodilatory response to muscle stimulation in the hamster cremaster muscle.

Differences in EDNO contribution to arteriolar diameters at rest and during functional dilation in striated muscle

1993 ◽  
Vol 265 (1) ◽  
pp. H146-H151 ◽  
Author(s):  
R. L. Hester ◽  
A. Eraslan ◽  
Y. Saito
Keyword(s):  
Striated Muscle ◽  
Physiological Role ◽  
Second Order ◽  
Muscle Stimulation ◽  
Third Order ◽  
First Order ◽  
Before And After ◽  
Arteriolar Vasodilation ◽  
Arteriolar Diameter

This study was designed to determine the physiological role of endothelium-dependent nitric oxide (EDNO) in the control of arteriolar diameter during rest and muscle stimulation. Diameters of first-, second-, and third-order arterioles in the superfused hamster cremaster muscle were measured before and throughout 1 min of field stimulation before and after inhibition of EDNO release. ENDO inhibition by intravenous N omega-nitro-L-arginine methyl ester (L-NAME) significantly attenuated the arteriolar vasodilation in response to 1 microM acetylcholine. First-order arterioles averaged 65 +/- 5 microns at rest and dilated to 86 +/- 6 microns during muscle stimulation (n = 9), second-order arterioles averaged 45 +/- 6 microns and dilated to 72 +/- 3 microns during muscle stimulation (n = 6), with third-order arterioles averaging 29 +/- 2 microns, and dilating to 53 +/- 3 microns during muscle stimulation (n = 7). EDNO inhibition significantly decreased both the resting diameter of first-order arterioles (57 +/- 4 microns) and functional dilation (68 +/- 3 microns; P <0.05). EDNO inhibition had no effect on the resting diameter of second-order arterioles (45 +/- 5 microns) yet significantly attenuated the functional dilation (64 +/- 4 microns; P < 0.05). EDNO inhibition had no effect on either the resting diameter of third-order arterioles (30 +/- 2 microns) or the functional dilation (49 +/- 2 microns).(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibition of phospholipase A2 attenuates functional hyperemia in the hamster cremaster muscle

1999 ◽  
Vol 276 (4) ◽  
pp. H1289-H1294 ◽  
Author(s):  
Louise C. Nuttle ◽  
Alison L. Ligon ◽  
Kathryn R. Farrell ◽  
Robert L. Hester
Keyword(s):  
Electrical Field Stimulation ◽  
Functional Hyperemia ◽  
Cremaster Muscle ◽  
Smooth Muscle Contractility ◽  
Nonspecific Effects ◽  
Common Precursor ◽  
The Common ◽  
Arteriolar Diameter

Arachidonic acid (AA) is the common precursor for several vasodilatory factors involved in the local control of blood flow. This study was designed to determine the role of phospholipase A2(PLA2) and AA release in functional hyperemia in the hamster cremaster muscle. The muscle was prepared for in vivo microscopy and subjected to electrical field stimulation for 1 min. First- and second-order arterioles dilated in response from a mean diameter of 66 ± 5 to 88 ± 7 μm ( n = 6). PLA2 was then inhibited with quinacrine (3 × 10−6M) for 60 min. PLA2 inhibition was verified by an attenuation of thrombin-induced vasodilation (2 U/ml). Quinacrine had no effect on resting arteriolar diameter but completely abolished functional hyperemia. Quinacrine also had no effect on dilation induced by superfusion of the preparation with 3 × 10−6–10−5M AA, 10−6–10−4M adenosine, or 10−6–10−4M sodium nitroprusside, ruling out nonspecific effects of quinacrine on smooth muscle contractility. These results indicate that functional hyperemia in the hamster cremaster muscle is dependent on PLA2 activation and the availability of AA.

Role of venular endothelium in control of arteriolar diameter during functional hyperemia

1994 ◽  
Vol 267 (3) ◽  
pp. H1227-H1231 ◽  
Author(s):  
Y. Saito ◽  
A. Eraslan ◽  
V. Lockard ◽  
R. L. Hester
Keyword(s):  
Silver Chloride ◽  
Muscle Stimulation ◽  
Functional Hyperemia ◽  
Cremaster Muscle ◽  
Silver Silver ◽  
Silver Silver Chloride ◽  
Arteriolar Vasodilation ◽  
Venular Endothelium

This study was designed to determine the importance of the venular endothelium in the vasodilation of adjacent arterioles during functional hyperemia. The hamster cremaster muscle was prepared for in vivo microscopy. Two silver-silver chloride electrodes were placed across the pedicle of the cremaster muscle, and a square-wave pulse (10 V amplitude, 1 ms duration, and 1 Hz frequency) was used to elicit muscle contraction. Muscle stimulation for 1 min resulted in a vasodilation of the first-order arterioles from 74 +/- 2 to 91 +/- 2 microns (n = 9, P < 0.05). After perfusion of the venule with air to disrupt the venular endothelium, there was no significant effect on the resting diameter, 73 +/- 3 microns, but the vasodilation associated with the muscle stimulation was significantly attenuated to 82 +/- 3 microns (P < 0.01). After completion of these experiments, the disruption of venular endothelium was confirmed by electron microscopy. The functional vasodilation of arterioles adjacent to venules with an intact endothelium (venules in which air did not enter) was retained after air perfusion (n = 6). These results suggest that the presence of the venular endothelium is important for the arteriolar vasodilation during functional hyperemia. We propose that the venular endothelium releases a relaxing factor responsible for a portion of the functional arteriolar vasodilation.

Intertextual Precision Expectations

2019 ◽  
pp. 107-116
Author(s):  
Karin Kukkonen
Keyword(s):  
Third Order ◽  
Structural Patterns ◽  
First Order ◽  
The Third ◽  
Order Probability

In the chapters that follow, the third-order probability design is developed. The third-order probability design revolves around how expectations about second- and first-order predictions are developed through structural patterns yielded by genre (III.1), textual gaps and shadow stories (III.2), and intertextual references to unfamiliar texts (III.3). The final chapter of the section, then, traces the tension between flexibility and constraint in probability designs.

Contribution of adenosine to arteriolar autoregulation in striated muscle

1983 ◽  
Vol 244 (4) ◽  
pp. H567-H576 ◽  
Author(s):  
R. J. Morff ◽  
H. J. Granger
Keyword(s):  
Blood Flow ◽  
Striated Muscle ◽  
Perfusion Pressure ◽  
Cremaster Muscle ◽  
Sprague Dawley ◽  
Red Blood Cell Velocity ◽  
Myogenic Factors ◽  
Bath Medium ◽  
Arteriolar Diameter

The contribution of adenosine to blood flow autoregulation in striated muscle was evaluated by direct in vivo visualization of arterioles in the rat cremaster muscle. Male Sprague-Dawley rats were anesthetized with pentobarbital sodium, and the cremaster muscle was surgically exposed and maintained in a controlled tissue bath environment with pH 7.40, CO2 tension (PCO2) congruent to 40 mmHg, and O2 tension (PO2) at either a high (congruent to 70 mmHg) or a low (congruent to 10 mmHg) value. Local adenosine activity was blocked in some animals by the addition of theophylline (3 X 10(-5) M) to the bath medium. Individual second (2A)- and third (3A)-order arterioles were observed via closed-circuit television microscopy, and blood flow in each arteriole was calculated from simultaneous measurements of arteriolar diameter and red blood cell velocity. Perfusion pressure to the animal's hindquarters was altered by varying the degree of occlusion of the sacral aorta; arteriolar diameter, velocity, and blood flow responses were plotted as a function of the varying pressure. Both 2A and 3A arterioles exhibited vasodilation and substantial superregulation of blood flow (increased blood flow with decreased perfusion pressure) when bath PO2 was low and adenosine activity was not blocked. Addition of theophylline to the cremaster bath medium significantly reduced the dilation and abolished superregulation, although substantial autoregulation remained. When bath PO2 was high, the degree of arteriolar dilation and autoregulation was reduced compared with the low bath PO2 responses, and blocking adenosine activity had no effect on the responses. These results support the concept that changes in local adenosine levels are involved in the autoregulatory responses observed in the rat cremaster muscle and that the magnitude of adenosine's contribution is directly related to the degree of tissue hypoxia. However, blocking adenosine activity did not totally abolish autoregulation, suggesting that other metabolic and/or myogenic factors may also be contributing to blood flow regulation in this tissue.

scholarly journals Achieving Seventh-Order Amplitude Accuracy in Leapfrog Integrations

2013 ◽  
Vol 141 (9) ◽  
pp. 3037-3051 ◽  
Author(s):  
Paul D. Williams
Keyword(s):  
Nonlinear System ◽  
Third Order ◽  
First Order ◽  
Time Stepping ◽  
The Third ◽  
Numerical Integrations ◽  
Seventh Order ◽  
Ocean Models ◽  
Stability And Accuracy ◽  
Fifth Order

Abstract The leapfrog time-stepping scheme makes no amplitude errors when integrating linear oscillations. Unfortunately, the Robert–Asselin filter, which is used to damp the computational mode, introduces first-order amplitude errors. The Robert–Asselin–Williams (RAW) filter, which was recently proposed as an improvement, eliminates the first-order amplitude errors and yields third-order amplitude accuracy. However, it has not previously been shown how to further improve the accuracy by eliminating the third- and higher-order amplitude errors. Here, it is shown that leapfrogging over a suitably weighted blend of the filtered and unfiltered tendencies eliminates the third-order amplitude errors and yields fifth-order amplitude accuracy. It is further shown that the use of a more discriminating (1, −4, 6, −4, 1) filter instead of a (1, −2, 1) filter eliminates the fifth-order amplitude errors and yields seventh-order amplitude accuracy. Other related schemes are obtained by varying the values of the filter parameters, and it is found that several combinations offer an appealing compromise of stability and accuracy. The proposed new schemes are tested in numerical integrations of a simple nonlinear system. They appear to be attractive alternatives to the filtered leapfrog schemes currently used in many atmosphere and ocean models.

scholarly journals Positive Solutions for Third-Order Boundary-Value Problems with the Integral Boundary Conditions and Dependence on the First-Order Derivatives

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Yanping Guo ◽  
Fei Yang
Keyword(s):  
Fixed Point ◽  
Green Function ◽  
Boundary Conditions ◽  
Boundary Value ◽  
Integral Boundary Conditions ◽  
Third Order ◽  
Integral Boundary ◽  
First Order ◽  
The Third ◽  
Nonnegative Continuous Function

By using a fixed point theorem in a cone and the nonlocal third-order BVP's Green function, the existence of at least one positive solution for the third-order boundary-value problem with the integral boundary conditionsx′′′(t)+f(t,x(t),x′(t))=0,t∈J,x(0)=0,x′′(0)=0, andx(1)=∫01g(t)x(t)dtis considered, wherefis a nonnegative continuous function,J=[0,1], andg∈L[0,1].The emphasis here is thatfdepends on the first-order derivatives.

scholarly journals MODIFIED WAVE EQUATION FOR SPINLESS PARTICLES AND ITS SOLUTIONS IN AN EXTERNAL MAGNETIC FIELD

2013 ◽  
Vol 28 (06) ◽  
pp. 1350014 ◽  
Author(s):  
S. I. KRUGLOV
Keyword(s):  
Magnetic Field ◽  
Wave Equation ◽  
External Magnetic Field ◽  
Quantum Mechanical ◽  
Third Order ◽  
Modified Dispersion Relation ◽  
First Order ◽  
The Third ◽  
Uniform External Magnetic Field ◽  
Schrödinger Form

The wave equation for spinless particles with the Lorentz violating term is considered. We formulate the third-order in derivatives wave equation leading to the modified dispersion relation. The first-order formalism is considered and the density matrix is obtained. The Schrödinger form of equations is presented and the quantum-mechanical Hamiltonian is found. Exact solutions of the wave equation are obtained for particles in the constant and uniform external magnetic field. The change of the synchrotron radiation radius due to quantum gravity corrections is calculated.

Perturbation treatment of the Hartree–Fock equations for the ground states of the boron-like ions

1969 ◽  
Vol 47 (7) ◽  
pp. 699-705 ◽  
Author(s):  
C. S. Sharma ◽  
R. G. Wilson
Keyword(s):  
Ground State ◽  
Atomic System ◽  
Ground States ◽  
Great Accuracy ◽  
Second Order ◽  
Expectation Values ◽  
Third Order ◽  
First Order ◽  
Hartree Fock ◽  
The Third

The first-order Hartree–Fock and unrestricted Hartree–Fock equations for the ground state of a five electron atomic system are solved exactly. The solutions are used to evaluate the corresponding second-order energies exactly and the third-order energies with great accuracy. The first-order terms in the expectation values of 1/r, r, r2, and δ(r) are also calculated.

scholarly journals Solitons, Rogues and Interaction Behaviors of Third-Order Nonlinear Schrodinger Equation

2022 ◽  
Author(s):  
Ren Bo ◽  
Shi Kai-Zhong ◽  
Shou-Feng Shen ◽  
Wang Guo-Fang ◽  
Peng Jun-Da ◽  
...  
Keyword(s):  
Bilinear Form ◽  
Rogue Wave ◽  
Soliton Solutions ◽  
Ultrashort Pulses ◽  
Rogue Waves ◽  
Third Order ◽  
First Order ◽  
The Third ◽  
Femtosecond Regime ◽  
Wave Limit

Abstract In this paper, we investigate the third-order nonlinear Schr\"{o}dinger equation which is used to describe the propagation of ultrashort pulses in the subpicosecond or femtosecond regime. Based on the independent transformation, the bilinear form of the third-order NLSE is constructed. The multiple soliton solutions are constructed by solving the bilinear form. The multi-order rogue waves and interaction between one-soliton and first-order rogue wave are obtained by the long wave limit in multi-solitons. The dynamics of the first-order rogue wave, second-order rogue wave and interaction between one-soliton and first-order rogue wave are presented by selecting the appropriate parameters. In particular parameters, the positions and the maximum of amplitude of rogue wave can be confirmed by the detail calculations.PACS numbers: 02.30.Ik, 05.45.Yv.

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