Regulation of heartbeat in Lymnaea by motoneurons containing FMRFamide-like peptides

Author:

Buckett K. J.1,Peters M.1,Dockray G. J.1,Van Minnen J.1,Benjamin P. R.1

Affiliation:

1. MRC Neurophysiology Research Group, School of Biological Sciences,University of Sussex, Falmer, Brighton, United Kingdom.

Abstract

1. Intracellular stimulation of single neurons in the Lymnaea CNS was carried out to identify heart motoneurons. 2. Two of the identified motoneurons, the E heart excitor (Ehe) cells, were shown to contain Phe-Met-Arg-Phe-NH2 (FMRFamide)-like peptides by immunocytochemical staining of dye-marked neurons and by radioimmunoassay (RIA) applied to extracts of single dissected cells. 3. Bursts of spikes in the Ehe cells increased heart rate, beat amplitude and muscle tonus. This response was mimicked by perfusion of exogenous FMRFamide at low concentration (10(-6) to 5 x 10(-8) M) through the interior of the intact heart. 4. Application of selective antagonists to 5-hydroxytryptamine (5-HT) and dopamine failed to block Ehe cardiac effects. 5. Detailed evidence that the Ehe cells were heart motoneurons was obtained. 1) Anatomic mapping using the dye Lucifer yellow showed Ehe cells had peripheral projections restricted mainly to the intestinal nerve, the only nerve known to innervate the heart. 2) Perfusion of the CNS with a saline containing Co2+ blocked central chemical synapses but did not affect activity of Ehe cells on the heart. 3) Simultaneous intracellular recordings from Ehe cells and auricle muscle fibers showed unitary excitatory junction potentials following with constant latency from spikes in Ehe cells. 6. The present study elucidates the role of FMRFamide in cardioregulation and provides the first evidence that it acts as an excitatory neurotransmitter on the snail heart.

Publisher

American Physiological Society

Subject

Physiology,General Neuroscience

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