Maximal rates of activation in electrically stimulated swine carotid media.

Author:

Singer H A,Murphy R A

Abstract

The kinetics of crossbridge phosphorylation and cellular activation rates in arterial smooth muscle are unknown, and the response rates are usually limited by agonist diffusion rates. In this study, electrical field stimulation (10-20 V AC, 60 Hz) was used to activate strips of swine carotid artery smooth muscle. Pretreatment with 0.5 microM phenoxybenzamine (PBZ) for 30 minutes significantly inhibited field stimulated stress due to norepinephrine released from adrenergic nerves. Addition of 1-10 mM tetraethylammonium ion (TEA) to PBZ-pretreated tissues allowed direct stimulation of muscle cells and significantly potentiated the response to field stimulation. Activation in field stimulated tissues pretreated with PBZ and TEA was strongly inhibited by the Ca2+-channel antagonist verapamil (0.5 microM for 15 minutes). Activation was rapid with myosin light chain (MLC)-phosphorylation values rising to greater than 50% of total MLC, with a half-time of approximately 1 second. Stress and stiffness development was biphasic and lagged with an estimated half-time for the first phase of 3 seconds. Stress and stiffness continued to slowly rise after 5 seconds of stimulation, while MLC phosphorylation declined significantly between 5 and 10 seconds to a nearly constant value of 35-40% for up to 60 seconds. Unloaded shortening velocity was maximal (0.067 Lo/sec) at the earliest time point examined (0.5 second), prior to significant stress development and at submaximal phosphorylation. Significant decreases in unloaded shortening velocity were observed after 10 seconds. These results show that the kinetics of phosphorylation and dephosphorylation and the rates of activation are very rapid in this arterial smooth muscle.

Publisher

Ovid Technologies (Wolters Kluwer Health)

Subject

Cardiology and Cardiovascular Medicine,Physiology

Cited by 44 articles. 订阅此论文施引文献 订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献

1. Biochemistry of the Contractile Proteins of Smooth Muscle;Biology of Vascular Smooth Muscle;2022

2. Biochemistry of the Contractile Proteins of Smooth Muscle;Biology of Vascular Smooth Muscle: Vasoconstriction and Dilatation;2017

3. On the thermodynamics of smooth muscle contraction;Journal of the Mechanics and Physics of Solids;2016-09

4. Mechanics of Vascular Smooth Muscle;Comprehensive Physiology;2015-12-15

5. A constitutive model for cytoskeletal contractility of smooth muscle cells;Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences;2014-04-08

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3