Table 1.

Serotonin receptor subtypes through gut-brain axis (adjusted according to O’Mahony et al., 2015).

Subtype	CNS function	ENS function
5-HT1A	mood, cognition, pain, sleep, neuroendocrine function	release of mediators, degranulation of enteric mast cells
5-HT2A	sleep, hallucinations	contraction of gut smooth muscle
5-HT2B	hyperphagia, grooming behavior	contraction of gut smooth muscle, visceral sensitivity
5-HT2C	mood, food intake	N/A
5-HT3	emesis, pain, release of other neurotransmitters	pain, secretory and motor responses
5-HT4	mood, cognition	contraction of smooth colonic muscle, prokinetic effect, neurotransmitter release
5-HT5A	mood, sensory perception, neuroendocrine functions	N/A
5-HT6	mood	N/A
5-HT7	mood, sleep	muscle relaxation