Neurotransmitters regulate β cells insulin secretion: A neglected factor

Table 1 Role of neurotransmitters in the islet

Name	Source	Receptor	Effect on pancreatic islet secretion
ACh	Vagus nerve	M3	↑↑↑
NO	Vagus nerve, beta cells	sGC	Low concentration ↑, high concentration ↓
GRP	Vagus nerve	GRPR	↑
VIP	Vagus nerve	VIP-2	↑
PACAP	Vagus nerve, gut-pancreas nerve	PACAP-3	↑
5-HT	Vagus nerve, gut-pancreas nerve, beta cells	Htr1	↑↑
NE	Sympathetic nerves	α2, β2	α2 receptors ↑, β2 receptors ↓↓
Galanin	Sympathetic nerves	GALR1	↓
NPY	Sympathetic nerves	Y2	↓
DA	Sympathetic nerves, beta cells	D2, D3	D2↑, D3↓
CGRP	Sensory nerves	CGRP	↓
SP	Sensory nerves	NK1	↑
Cholecystokinin	Sensory nerves	CCK	↓

“↑” represents the promotion of insulin secretion; “↓” represents the inhibition of insulin secretion. 5-HT: 5-hydroxytryptamine; ACh: Acetylcholine; CCK: Cholecystokinin; CGRP: Calcitoningenerelatedpeptide; DA: Dopamine; GRP: Gastrin releasing peptide; NE: Norepinephrine; NO: Nitric oxide; NPY: Neuropeptide Y; PACAP: Pituitary adenylate cyclase activating polypeptide; SP: Substance P; VIP: Vasoactive intestinal peptide.