1000/1000
Hot
Most Recent
5-Hydroxytryptamine (5-HT), or serotonin, plays a crucial role as a neuromodulator and/or neurotransmitter of several nervous system functions. Its actions are complex, and depend on multiple factors, including the type of effector or receptor activated. Briefly, 5-HT can activate: (i) metabotropic (G-protein-coupled) receptors to promote inhibition (5-HT1, 5-HT5) or activation (5-HT4, 5-HT6, 5-HT7) of adenylate cyclase, as well as activation (5-HT2) of phospholipase C; and (ii) ionotropic receptor (5-HT3), a ligand-gated Na+/K+ channel. Regarding blood pressure regulation (and beyond the intricacy of central 5-HT effects), this monoamine also exerts direct postjunctional (on vascular smooth muscle and endothelium) or indirect prejunctional (on autonomic and sensory perivascular nerves) effects. At the prejunctional level, 5-HT can facilitate or preclude the release of autonomic (e.g., noradrenaline and acetylcholine) or sensory (e.g., calcitonin gene-related peptide) neurotransmitters facilitating hypertensive or hypotensive effects. Hence, we cannot formulate a specific impact of 5-HT on blood pressure level, since an increase or decrease in neurotransmitter release would be favoured, depending on the type of prejunctional receptor involved.
5-HT Receptor |
Receptor Subtype | Agonists | Antagonists | Some Functions | Canonical Transduction System |
---|---|---|---|---|---|
5-HT1 | 5-HT1A | 8-OH-DPAT | WAY 100635 | Central hypotension | G-protein coupled receptor (Gi) |
5-HT1B | Sumatriptan CP-93,129 (rodents) |
SB224289 | Vasoconstriction, sympatho-inhibition | ||
5-HT1D | PNU-109291 PNU-142633 |
BRL15572 | Autoreceptor, sympatho-inhibition | ||
5-HT1e * | 5-HT >> 5-CT LY334370 | Methiothepin (non-selective) |
Unknown | ||
5-HTF | LY344864, lasmiditan, LY334370 | Methysergide (non-selective) |
(−) Trigeminal system | ||
5-HT5 | 5-HT5A | 5-HT, ergotamine | SB699551 | Cardiac sympatho-inhibition in rats | |
5-HT5b * | 5-CT (non-selective) | Unknown | Unknown | ||
5-HT4 | - | Renzapride, BIMU8, ML10302, SC53116 | GR 113808 SB204070 | (+) Neuronal activity, vasodilatation, tachycardiain pigs and humans |
G-protein coupled receptor (Gs) |
5-HT6 | - | 5-MeO-T ≥ 5-HT SB357134 SB271046 |
Ro 630563 | Memory, not involved in cardiovascular regulation |
|
5-HT7 | - | 5-CT>>5-HT AS-19 |
SB269970 SB258719 | Circadian rhythm, vasodila- tation, tachycardia in cats |
|
5-HT2 | 5-HT2A | DOI, DOB α-methyl-5-HT |
MDL100907 Ketanserin |
Vasoconstriction, plateletaggregation | G-protein coupled receptor (Gq) |
5-HT2B | DOI, BW723C86 α-methyl-5-HT |
SB204741 RS-127445 |
Vasoconstriction, release of NO | ||
5-HT2C | DOI, Ro 60-0175 α-methyl-5-HT |
SB242084 RS-102221 |
CSF production | ||
5-HT3 | Pentameric ion channel ** | Phenylbiguanide 2-methyl-5-HT |
Tropisetron Granisetron MDL-72222 |
(+) Neuronal activity, reflex bradycardia |
Ligand-gated ion channel |