The last two authors contributed equally to this work.
Identification of μ- and κ-opioid receptors as potential targets to regulate parasympathetic, sympathetic, and sensory neurons within rat intracardiac ganglia
Version of Record online: 20 MAY 2010
Copyright © 2010 Wiley-Liss, Inc.
Journal of Comparative Neurology
Volume 518, Issue 18, pages 3836–3847, 15 September 2010
How to Cite
Mousa, S. A., Shaqura, M., Schäper, J., Huang, W., Treskatsch, S., Habazettl, H., Abdul-Khaliq, H. and Schäfer, M. (2010), Identification of μ- and κ-opioid receptors as potential targets to regulate parasympathetic, sympathetic, and sensory neurons within rat intracardiac ganglia. J. Comp. Neurol., 518: 3836–3847. doi: 10.1002/cne.22427
- Issue online: 13 JUL 2010
- Version of Record online: 20 MAY 2010
- Accepted manuscript online: 20 MAY 2010 12:00AM EST
- Manuscript Accepted: 25 APR 2010
- Manuscript Revised: 11 MAR 2010
- Manuscript Received: 18 JAN 2010
- Indexing terms: intracardiac ganglia;
- opioid receptors;
- sensory nerves
Recent interest has been focused on the opioid regulation of heart performance; however, specific allocation of opioid receptors to the parasympathetic, sympathetic, and sensory innervations of the heart is scarce. Therefore, the present study aimed to characterize such specific target sites for opioids in intracardiac ganglia, which act as a complex network for the integration of the heart's neuronal in- and output. Tissue samples from rat heart atria were subjected to RT-PCR, Western blot, radioligand-binding, and double immunofluorescence confocal analysis of μ (M)- and κ (K)-opioid receptors (ORs) with the neuronal markers vesicular acetylcholine transporter (VAChT), tyrosine hydroxylase (TH), calcitonin gene-related peptide (CGRP), and substance P (SP). Our results demonstrated MOR- and KOR-specific mRNA, receptor protein, and selective membrane ligand binding. By using immunofluorescence confocal microscopy, MOR and KOR immunoreactivity were colocalized with VAChT in large-diameter parasympathetic principal neurons, with TH-immunoreactive small intensely fluorescent (SIF) cells, and on nearby TH-IR varicose terminals. In addition, MOR and KOR immunoreactivity were identified on CGRP- and SP-IR sensory neurons throughout intracardiac ganglia and atrial myocardium. Our findings show that MOR and KOR are expressed as mRNA and translated into specific receptor proteins on cardiac parasympathetic, sympathetic, and sensory neurons as potential binding sites for opioids. Thus, they may well play a role within the complex network for the integration of the heart's neuronal in- and output. J. Comp. Neurol. 518:3836–3847, 2010. © 2010 Wiley-Liss, Inc.