Nonselective cation channels coupled with tachykinin receptors in rat sensory neurons

Author:

Inoue K.1,Nakazawa K.1,Inoue K.1,Fujimori K.1

Affiliation:

1. Division of Pharmacology, National Institute of Health Sciences,Tokyo, Japan.

Abstract

1. Effects of substance P (SP) and other tachykinins on membrane currents were investigated using whole cell voltage clamp in cultured sensory neurons isolated from rat dorsal root ganglia. 2. SP (100 nM) evoked an inward current in two-thirds of the cells at negative potentials. In most of the cells that generated the inward current in response to SP, capsaicin also activated an inward current. The SP-evoked inward current was not observed in cells loaded with 2 mM guanosine 5'-O-(2-thiodiphosphate) (GDP beta S). 3. Neurokinin A (NKA) or neurokinin B (NKB) also activated an inward current. At 100 nM of each agonist, the order was NKB > NKA > SP with respect to activated current amplitude. 4. The tachykinin-activated current was reversed around +10 mV with a standard extracellular solution containing 140 mM NaCl. The reversal potential became more negative when extracellular NaCl was reduced by substituting with sucrose. The inward current was also activated in cells bathed in an extracellular solution containing Cs+, tetraethylammonium (TEA) or N-methyl-D-glucamine (NMDG) as a major cation instead of Na+. The order of permeability, determined from the reversal potential of the current, was Cs+ not equal to Na+ > TEA > NMDG. The amplitude of the inward current activated by NKB was increased when extracellular Na+ was replaced with Cs+, TEA or NMDG. 5. Permeability of Ca2+ was tested using an extracellular solution containing Ca2+ as the only cation (111.8 mM Ca2+ outside). Under this condition, NKB evoked an inward current that reversed around +30 mV. 6. The results suggest that SP and other tachykinins activate nonselective cation channels, which are also permeable to Ca2+, through receptors which are more responsive to NKB than to SP or NKA. The channel activation may serve as a mechanism underlying tachykinin-mediated excitatory neurotransmission in sensory neurons.

Publisher

American Physiological Society

Subject

Physiology,General Neuroscience

Cited by 48 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

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