Modulation of peripheral sympathetic nerve transmission

Area of Science:

• Neuroscience and Pharmacology
• Autonomic Nervous System Regulation

Background:

• Significant advancements in understanding sympathetic outflow modulation to neuroeffector organs, particularly vascular tissue, have occurred over the last 15 years.
• Norepinephrine release from sympathetic neurons is regulated by both negative and positive feedback mechanisms.

Purpose of the Study:

• To review the inhibitory and facilitatory mechanisms controlling sympathetic neurotransmission.
• To highlight the clinical relevance of these mechanisms in various cardiovascular and neurological conditions.

Main Methods:

• Review of literature on presynaptic and postsynaptic receptor interactions influencing sympathetic nerve activity.
• Discussion of the roles of various neurotransmitters and neuromodulators, including norepinephrine, dopamine, acetylcholine, and others.

Main Results:

• Presynaptic alpha 2-adrenergic receptors, along with dopaminergic (DA2), muscarinic, opioid, prostaglandin, adenosine (A1), and histamine (H2) receptors, inhibit norepinephrine release.
• Gamma-aminobutyric acid and serotonin also reduce sympathetic nerve activity.
• Angiotensin II and beta 2-adrenergic receptor activation facilitate norepinephrine release.

Conclusions:

• Understanding sympathetic modulation is crucial for treating conditions like hypertension, heart failure, orthostatic hypotension, and withdrawal syndromes.
• Specific receptor targets offer therapeutic potential for managing autonomic dysfunction.