| Name | Mechanism of action | Associated with |
| Serotonin (5-HT) [21, 35] | Vasoconstriction or vasodilatation Increased gut motility Increased secretion of water, sodium, chloride, and potassium | Diarrhoea, flushing, palpitations |
| Tachykinins (substance K, substance P, neuropeptide K, neurokinin A) [36ā38] | Cutaneous vasodilatation, tachycardia, hypotension, and increased small intestine motility | Diarrhoea, flushing, palpitations |
| Histamine [5, 39] | Vasodilatation | Flushing, wheezing, palpitations |
| Kallikrein [40] | Release/stimulation of bradykinin resulting in hypotension | Flushing, palpitations |
| Prostaglandin [41] | Increased intestinal motility and fluid secretion Vasodilatation | Diarrhoea, flushing, palpitations |
| Catecholamines (norepinephrine) [42, 43] | Initiate cascade resulting in serotonin release | Flushing, palpitations |
| Motilin [44] | Initiation of interdigestive migrating motor complex (IMMC) | Diarrhoea |
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