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Abstract

Immunoreactivities (IR) for catecholamine-synthesizing enzymes tyrosine hydroxylase (TH), dopamine-beta-hydroxylase (DbetaH), phenylethanolamine N-methyl transferase (PNMT), serotonin-synthesizing enzyme tryptophan hydroxylase, and neuropeptide Y were investigated in the intrinsic cardiac nervous system of 27-40-day-old rats using fluorescent immunohistochemistry. Individual neurons were identified by the general neuronal marker protein gene product 9.5. The presence of DbetaH and PNMT in the atrial specimens was verified using reverse transcriptase-polymerase chain reaction. Two types of catecholamine-handling intrinsic ganglion neurons were observed: small intensely fluorescent (SIF) cells and large-diameter neurons. SIF cells exhibited TH- and tryptophan hydroxylase-IR, but they were not positive for DbetaH. In contrast, large-diameter intrinsic TH-positive neurons, showing in majority also NPY-IR, displayed also DbetaH- and PNMT-IR, thus indicating the capacity for the synthesis of norepinephrine and epinephrine, respectively. In conclusion, the SIF cells are most probably dopaminergic and serotonergic neurons, whereas large-diameter intrinsic cells seem to represent a subpopulation of norepinephrine- and/or epinephrine-secreting neurons.

Autonomic cardiac innervation

“…However, there is certainly some species-variability in neurochemistry, and the evidence for a complete adrenergic panel in one species is debatable. Based on these data, however, some investigators have suggested that a pure adrenergic population, or a dual cholinergic/adrenergic population, may reside with cell bodies actually present within the cardiac ganglia 17 , 348 - 355 . At least in the rat, we were able to definitively demonstrate that glyoxcylic acid histofluorescence for catecholamines was absent from large (20–40 μm diameter) cardiac ganglion neurons, but was present in small (8–10 μm) intensely fluorescent (SIF) cells 199 .…”

Distribution and neurochemical characteristic of the cardiac nerve structures in the heart of chinchilla (Chinchilla laniger Molina)

“…The regulation of the heart function by the autonomic nervous system has two main components: an adrenergic component, which stimulates the heart and conduction system, and a cholinergic component, which inhibits them [29,30]. It is also known that the sympathetic part consists mainly of nerve fibers, while the parasympathetic part involves both fibers and nerve cells.…”

Substance P Receptor in the Rat Heart and Regulation of Its Expression in Long-Term Diabetes

“…It is a biochemically and functionally very heterogeneous group of interconnected neurons containing both cholinergic and adrenergic neurons. These neurons contain in addition to classical mediator also one or more neuropeptides ( Slavikova et al, 2003 ). All together are responsible for integration of sensory information from the heart with information coming from CNS ( Kukanova and Mravec, 2006 ).…”