Expression of catecholaminergic characteristics by primary sensory neurons in the normal adult rat in vivo.

Abstract

Expression of catecholaminergic characteristics by primary sensory neurons was examined in the vagal nodose and glossopharyngeal petrosal ganglia of the normal. adult rat in vivo. Catecholaminergic phenotypic expression was documented by immunocytochemical localization of tyrosine hydroxylase (TyrOHase; EC 1.14.16.2), radiochemical assay of specific TyrOHase catalytic activity, and cytochemical localization of formaldehydeinduced catecholamine fluorescence (FIF) within principal, ganglion cells. The TyrOHase-containing cells exhibited morphologic features typical of primary sensory neurons, such as an initial axon glomerulus and a single, bifurcating neurite process. These cells were distinguished from TyrOHase-and FIF-positive small intensely fluorescent cells by size, morphology, and staining intensity. TyrOHase-containing neurons appeared to be insensitive to neonatal treatment with 6-hydroxydopamine, thereby distinguishing them from sympathetic neurons. Nodose and petrosal ganglia of adult rats exhibited TyrOHase catalytic activity, linear with respect to tissue concentration over a 10-fold range, indicating that the immunoreactive enzyme was functional. Transection of specific ganglionic nerve roots depleted TyrOHase catalytic activity and neuronal immunoreactivity within the petrosal ganglion, suggesting that target organ innervation regulates enzyme levels within ganglion perikarya. Our study indicates that primary sensory neurons express catecholaminergic transmitter traits in the normal adult rat. Consequently, in the periphery, catecholaminergic characters are not restricted to the sympathoadrenal axis but are expressed by functionally and embryologically diverse populations of autonomic neurons.rons, small intensely fluorescent (SIF) cells, and adrenomedullary cells. The present study was undertaken to determine whether catecholaminergic characters are also normally expressed by other classes of peripheral neurons. We examined expression of catecholamine biosynthetic enzymes and formaldehyde-induced catecholamine fluorescence (FIF) in primary sensory neurons in the nodose ganglion (NG) and petrosal ganglion (PG) of the adult rat. The enzymes were tyrosine hydroxylase (TyrOHase; tyrosine 3-monooxygenase, EC 1.14.16.2), which catalzyes the rate-limiting step in catecholamine biosynthesis (6), and dopamine P-hydroxylase (DBOHase; dopamine f3-monooxygenase, EC 1.14.17.1) and phenylethanolamine N-methyltransferase (PNMTase, EC 2.1.1.28), which catalyze the synthesis of norepinephrine and epinephrine, respectively.The NG and PG contain the cells of origin of vagal and glossopharyngeal afferent fibers, respectively. Avian studies demonstrated that NG and PG neurons are derived from the embryonic epibranchial placodes (7). These neurons were selected for the present study, therefore, because they differ functionally and embryologically from sympathetic neurons. Our study was performed in adults, because (transient) catecholaminergic expression had already been demonstrated in presumptive neuroblasts ...

Serotonergic neuroepithelial cells of the skin in developing zebrafish: morphology, innervation and oxygen-sensitive properties

“…In a similar manner, chemoreceptive NECs of the gills are innervated by multiple sources, including catecholaminergic nerves with ultrastructural features of sensory nerve terminals (Dunel-Erb et al, 1982;Bailly et al, 1992;Bailly, 2009). Moreover, the rat carotid body receives innervation by catecholaminergic primary sensory neurons of glossopharyngeal and vagal ganglia, including those that display dopaminergic properties and innervate chemosensory type I cells (Katz et al, 1983;Finley et al, 1992).…”

Mice Lacking Brain-Derived Neurotrophic Factor Exhibit Visceral Sensory Neuron Losses Distinct from Mice Lacking NT4 and Display a Severe Developmental Deficit in Control of Breathing

“…Moreover, hypoxic chemosensory drive in these animals is reduced severely. These respiratory abnormalities correlate with a severe loss of DA neurons in the NPG, a large proportion of which are believed to transmit chemosensory information from the carotid body (Katz et al, 1983;Katz and Black, 1986;Finley et al, 1992). Because ventilation and metabolic rate also are influenced by body temperature, particularly in newborn animals, further studies will be required to evaluate potential contributions of these factors to the knockout respiratory phenotype.…”

“…A large proportion of these cells innervate the carotid body (Katz et al, 1983;Katz and Black, 1986;Finley et al, 1992), a chemoreceptor organ that provides tonic excitatory drive to ventilation (Dejours, 1962) and the primary site at which hypoxemia triggers homeostatic cardiorespiratory reflexes (Heymans and Heymans, 1927;Heymans and Bouckaert, 1930). We therefore hypothesized that loss of these cells would result in abnormal breathing, possibly contributing to the lethality associated with loss of BDNF or TrkB.…”

Expression of Varicella-Zoster Virus Immediate-Early Regulatory Protein IE63 in Neurons of Latently Infected Human Sensory Ganglia

“…Whereas light-brown lipofuscin granules were mentioned as a possible source of interference in previous reports examining VZV protein expression, the darker neuromelanin granules were not. Neuromelanin is an age-related pigment that accumulates in autophagic vacuoles (referred to as granules) in the cytoplasm of catecholaminergic neurons, which are primarily found in the substantia nigra of the midbrain; however, these neurons also comprise a subpopulation in spinal ganglia of many species, including humans (6,18,23,35,48). Neuromelanin has been described in human TGG and DRG (3,4,10,20,22,44).…”