Catecholaminergic microcircuitry controlling the output of airway-related vagal preganglionic neurons

Departments of 1  Physiology and Biophysics and 5  Pharmacology, Howard University College of Medicine, Washington, DC 20059; and Departments of 2  Pediatrics, 3  Anatomy, and 4  Psychiatry, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106 In this study, we have investigated...

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Published in:Journal of applied physiology (1985) 2003-05, Vol.94 (5), p.1999-2009
Main Authors: Haxhiu, Musa A, Kc, Prabha, Neziri, Burim, Yamamoto, Bryan K, Ferguson, Donald G, Massari, V. John
Format: Article
Language:English
Subjects:
Animals
Autonomic Fibers, Preganglionic - physiology
Autonomic Fibers, Preganglionic - ultrastructure
Biological and medical sciences
Catecholamines - physiology
Chromatography, High Pressure Liquid
Ferrets
Fundamental and applied biological sciences. Psychology
Horseradish Peroxidase
Immunohistochemistry
Male
Microdialysis
Microscopy, Electron
Microscopy, Fluorescence
Motor control and motor pathways. Reflexes. Control centers of vegetative functions. Vestibular system and equilibration
Muscle Relaxation
Muscle, Smooth - innervation
Muscle, Smooth - physiology
Nerve Net - physiology
Nervous system
Neurons
Neurons - physiology
Norepinephrine - metabolism
Norepinephrine - physiology
Receptors, Adrenergic, alpha-2 - metabolism
Respiratory system
Respiratory System - innervation
Vagus Nerve - physiology
Vagus Nerve - ultrastructure
Vertebrates: nervous system and sense organs
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Summary:Departments of 1  Physiology and Biophysics and 5  Pharmacology, Howard University College of Medicine, Washington, DC 20059; and Departments of 2  Pediatrics, 3  Anatomy, and 4  Psychiatry, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106 In this study, we have investigated the ultrastructure and function of the catecholaminergic circuitry modulating the output of airway-related vagal preganglionic neurons (AVPNs) in ferrets. Immunoelectron microscopy was employed to characterize the nature of catecholaminergic innervation of AVPN at the ultrastructural level. In addition, immunofluorescence was used to examine the expression of the 2A -adrenergic receptor ( 2A -AR) on AVPNs, and norepinephrine release within the rostral nucleus ambiguous (rNA) was measured by using microdialysis. Physiological experiments were performed to determine the effects of stimulation of the noradrenergic locus coeruleus (LC) cell group on airway smooth muscle tone. The results showed that 1 ) catecholaminergic nerve endings terminate in the vicinity of identified AVPNs but very rarely form axosomatic or axodendritic synapses with the AVPNs that innervate the extrathoracic trachea; 2 ) AVPNs express the 2A -AR; 3 ) LC stimulation-induced norepinephrine release within the rNA region was associated with airway smooth muscle relaxation; and 4 ) blockade of 2A -AR on AVPNs diminished the inhibitory effects of LC stimulation on airway smooth muscle tone. It is concluded that a noradrenergic circuit originating within the LC is involved in the regulation of AVPN activity within the rNA, and stimulation of the LC dilates the airways by the release of norepinephrine and activation of 2A -AR expressed by AVPNs, mainly via volume transmission. synaptic transmission; volume transmission; locus coeruleus; nucleus ambiguus; 2A -adrenergic receptors
ISSN:8750-7587
1522-1601
DOI:10.1152/japplphysiol.01066.2002