Premium
Developmental expression of δ‐opioid receptors during maturation of the parasympathetic, sympathetic, and sensory innervations of the neonatal heart: Early targets for opioid regulation of autonomic control
Author(s) -
Mousa Shaaban A.,
Shaqura Mohammed,
Schäper Jörn,
Treskatsch Sascha,
Habazettl Helmut,
Schäfer Michael,
AbdulKhaliq Hashim
Publication year - 2011
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.22560
Subject(s) - vesicular acetylcholine transporter , biology , calcitonin gene related peptide , medicine , endocrinology , catecholaminergic , tyrosine hydroxylase , intracardiac injection , catecholaminergic cell groups , substance p , neuroscience , neuropeptide , microbiology and biotechnology , receptor , cholinergic , choline acetyltransferase , catecholamine , dopamine
Evidence is accumulating regarding the local opioid regulation of heart function. However, the exact anatomical location of δ‐opioid receptors (DORs) and expression during maturation of the autonomic and sensory innervations of the neonatal heart is unknown. Therefore, we aimed to characterize target sites for opioids in neonatal rat heart intracardiac ganglia at postnatal day (P)1, P7 and adulthood (P56–P84). Rat heart atria were subjected to reverse‐transcriptase polymerase chain reaction, Western blot, radioligand binding, and immunofluorescence confocal analysis of DORs with the neuronal markers vesicular acetylcholine transporter (VAChT), tyrosine hydroxylase (TH), calcitonin gene‐related peptide (CGRP), and substance P (SP). Our results demonstrated DOR mRNA, protein, and binding sites that gradually increased from P1 toward adulthood. Immunofluorescence confocal microscopy showed DOR co‐localized with VAChT in large‐diameter principal neurons, TH‐immunoreactive (IR) small intensely fluorescent (SIF) catecholaminergic cells, and CGRP‐ or SP‐IR afferent nerve terminals arborizing within intracardiac ganglia and atrial myocardium. Co‐expression of DOR with VAChT‐IR neurons was observed from the first day of birth (P1). In contrast, DORs on TH‐IR SIF cells or CGRP‐IR fibers were not observed in intracardiac ganglia of P1, but rather in P7 rats. The density of nerve fibers in atrial myocardium co‐expressing DORs with different neuronal markers increased from neonatal age toward adulthood. In summary, the enhanced DOR expression parallel to the maturation of cardiac parasympathetic, sympathetic, and sensory innervation of the heart suggests that the cardiac opioid system is an important regulator of neonatal and adult heart function through the autonomic nervous system. J. Comp. Neurol. 519:957–971, 2011. © 2010 Wiley‐Liss, Inc.