Differentiation of noradrenergic and dopaminergic neurons in the cardiovascular system
M Hadjiconstantinou1, J C Papademetriou, N H Neff
1Department of Pharmacology, The Ohio State University College of Medicine, Columbus, OH 43210, U.S.A.
Insights
The rat cardiovascular system contains dopamine (DA) and norepinephrine (NE). Selective depletion studies suggest independent dopaminergic and noradrenergic elements, indicating DA is not solely a precursor for NE.
Area of Science:
- Neuropharmacology
- Cardiovascular Physiology
Background:
- Dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), and norepinephrine (NE) are key catecholamines in the cardiovascular system.
- Understanding the distinct roles and origins of these neurotransmitters is crucial for cardiovascular research.
Purpose of the Study:
- To investigate the presence and distribution of catecholamines in the rat cardiovascular system.
- To determine if dopamine serves solely as a precursor for norepinephrine.
- To explore the independent dopaminergic and noradrenergic elements within this system.
Main Methods:
- Selective depletion of catecholamines using 6-hydroxydopamine (6-HODA) and N-(2-chloroethyl)N-ethyl-2-bromobenzylamine (DSP-4).
- Pretreatment with desipramine to differentiate between dopaminergic and noradrenergic pathways.
- Assay of NE, DA, and DOPAC in rat and human cardiovascular tissues.
Main Results:
- 6-HODA administration partially depleted all catechols (DA, DOPAC, NE).
- Desipramine pretreatment followed by 6-HODA selectively depleted DA and DOPAC.
- DSP-4 administration partially depleted NE with minimal impact on DA and DOPAC.
- Catecholamine distribution in human vessels mirrored findings in animal models.
Conclusions:
- The rat cardiovascular system possesses independent dopaminergic and noradrenergic components.
- Dopamine is not exclusively a precursor for norepinephrine.
- Findings in rat models are consistent with catecholamine distribution in human cardiovascular tissues.
Abstract:
Dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and norepinephrine (NE) are present in the rat cardiovascular system. All of the catechols can be partially depleted by administering 6-hydroxydopamine (6-HODA). When animals are pretreated with desipramine before 6-HODA, there is a selective partial depletion of DA and DOPAC. NE can be partially depleted with minimal effects on DA and DOPAC by administering N-(2-chloroethyl)N-ethyl-2-bromobenzylamine (DSP-4). These results are consistent with the hypothesis that independent dopaminergic and noradrenergic elements are present in the rat cardiovascular system and that DA is not solely a precursor for NE. NE, DA and DOPAC were assayed in human vessels and the pattern of distribution of the catechols is consistent with the results reported for animals.
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