Vasomotor Responses of Rat Coronary Arteries to Isoflurane and Halothane Depend on Preexposure Tone and Vessel Size

Abstract Background The authors previously reported that in rabbits, isoflurane exhibited a heterogeneous vasomotor effect, constricting small resistance coronary arteries and dilating larger conductance arteries. The novelty of isoflurane-induced constriction of small coronary arteries raised the question of whether the finding depended on the unique experimental setup or species used. The purpose of this study was to address these questions. Therefore, a second species was studied, namely rats, as well as a second volatile anesthetic, halothane. In addition, the dependence of the vasomotor effect on the preexisting tone of the vessels was examined.

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HETEROGENEOUS VASOMOTOR RESPONSES OF RABBIT CORONARY ARTERIES TO ISOFLURANE

Anesthesiology ◽

10.1097/00000542-199409001-00776 ◽

1994 ◽

Vol 81 (SUPPLEMENT) ◽

pp. A777

Author(s):

K. W. Park ◽

H. B. Dai ◽

E. Lowenstein ◽

A. Darvish ◽

F. W. Sellke

Keyword(s):

Coronary Arteries ◽

Vasomotor Responses

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Serum cholesterol level, cigarette smoking, and vasomotor responses to L-arginine in narrowed epicardial coronary arteries

The American Journal of Cardiology ◽

10.1016/s0002-9149(99)00781-x ◽

2000 ◽

Vol 85 (4) ◽

pp. 500-503 ◽

Cited By ~ 9

Author(s):

Costas Tentolouris ◽

Dimitris Tousoulis ◽

Graham J Davies ◽

Christodoulos Stefanadis ◽

Pavlos Toutouzas

Keyword(s):

Cigarette Smoking ◽

Cholesterol Level ◽

Coronary Arteries ◽

Serum Cholesterol ◽

Serum Cholesterol Level ◽

Vasomotor Responses

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Factors affecting the efficiency of the catalytic purification of air from pollutants

10.35688/2413-8452-2015-01-004 ◽

2015 ◽

Vol 1 ◽

pp. 15-18

Author(s):

Kurylev V.V. ◽

Vladimirov S.N.

Keyword(s):

High Speed ◽

Air Flow ◽

Nonwoven Fabric ◽

Porous Ceramics ◽

Air Purification ◽

Experimental Setup ◽

Factors Affecting ◽

Nonwoven Materials ◽

Small Resistance ◽

Static Resistance

In the article, the influence of the intensity of ultraviolet radiation to the media photocatalytic air purification. Conducted research and made a choice of material based on its durability performance, resistance and efficiency of air purification. It is noted that the substrate can be nonwoven materials, glass balls of various size, porous ceramics, paper, etc. Defined methods of applying the photocatalyst to the carrier material. Designed and manufactured experimental setup to determine the static resistance to air flow. Reviewed the design of the experimental setup to determine the static resistance to air flow. Based on the obtained results we note that the minimum resistance to any air flow creates a synthetic non-woven material based on polyethylene terephthalate. Nonwoven fabric based on natural wool keeps the particles of photocatalyst and creates a relatively small resistance at high speed air flow. Media made from sintered glass beads do not lose the nanoparticles at any speed of flow.

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Brimonidine evokes heterogeneous vasomotor response of retinal arterioles: diminished nitric oxide-mediated vasodilation when size goes small

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.01281.2005 ◽

2006 ◽

Vol 291 (1) ◽

pp. H231-H238 ◽

Cited By ~ 18

Author(s):

Robert H. Rosa ◽

Travis W. Hein ◽

Zhaoxu Yuan ◽

Wenjuan Xu ◽

Melissa I. Pechal ◽

...

Keyword(s):

Nitric Oxide ◽

Blood Flow ◽

No Synthase ◽

Second Order ◽

Retinal Blood Flow ◽

Vasomotor Response ◽

Vessel Size ◽

First Order ◽

Vasomotor Responses ◽

Retinal Arterioles

Brimonidine, an α2-adrenergic receptor (AR) agonist, has been employed in the treatment of glaucoma due to its beneficial effects on intraocular pressure reduction and neuroprotection. In addition, some studies have implicated that brimonidine might influence ocular blood flow; however, its effect on the retinal microcirculation has not been documented. Herein, we examined the vasomotor action of brimonidine on different branching orders of retinal arterioles in vitro and determined the contribution of the α2-AR subtype and the role of endothelium-derived nitric oxide (NO) in this vasomotor response. First- and second-order retinal arterioles of pigs were isolated, cannulated, and pressurized for functional studies. Videomicroscopic techniques were employed to record diameter changes in response to brimonidine. RT-PCR was performed for detection of α-AR and endothelial NO synthase (eNOS) mRNA in retinal arterioles. All first-order arterioles (82 ± 2 μm ID) dilated dose dependently to brimonidine (0.1 nM to 10 μM) with 10% dilation at the highest concentration. Second-order arterioles (50 ± 1 μm ID) responded heterogeneously with either dilation or constriction. The incidence and magnitude of vasoconstriction were increased with increasing brimonidine concentration. Administration of the NO synthase inhibitor NG-nitro-l-arginine methyl ester abolished the brimonidine-induced vasodilation in first- and second-order arterioles. Regardless of vessel size, vasomotor responses (i.e., vasodilation and vasoconstriction) of retinal arterioles were sensitive to the α2-AR antagonist rauwolscine. Consistent with the functional data, α2A-AR and eNOS mRNAs were detected in retinal arterioles. Collectively, our data demonstrate that brimonidine at clinical doses evokes a consistent NO-dependent vasodilation in first-order retinal arterioles but a heterogeneous response in second-order arterioles. These vasomotor responses are mediated by the activation of α2-AR. It appears that brimonidine, depending on the concentration and vessel size, may alter local retinal blood flow.

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