Table 1.

The anatomical and functional features of the locus coeruleus in non-mammalian vertebrates.

Class	Contents	Species	References
Fish	Identified anatomical location, cell types, cell markers and cell morphology in the locus coeruleus (LC).	Electric fish, Apteronotus leptorhynchus Chondrostean fish, Acipenser baeri Chondrostean fish, Huso huso Short-lived fish, Nothobranchius furzeri Cartilaginous fish, Hydrolagus colliei Goldfish, Carassius auratus Zebrafish, Danio rerio	[8,17,58,62,63,78,82,86,138,139]
	Ascending and descending pathways.	Zebrafish, Danio rerio	[13,19,20,79,137]
	Circuit: hypocretin(Hcrt) and melanin-concentrating hormone(MCH) neurons project to the vicinity of the LC.	Goldfish, Carassius auratus Zebrafish, Danio rerio	[14,98,140]
	Regulating sleep and wakefulness.	Goldfish, Carassius auratus Zebrafish, Danio rerio	[14,93,98,140,141]
	Development: the LC cell appears between 8–12 hour post fertilization (hpf), differentiates between 24–48 hpf.	Zebrafish, Danio rerio	[7,77,78,79,81]
	Modulating brain states, including anxiety, anethesia, and passivity.	Zebrafish, Danio rerio	[15,75,99]
	Highly and specifically expression of copper transporter.	Zebrafish, Danio rerio	[93]
Amphibians	Ascending and descending pathways.	Newt, Triturus cristatus Newt, Pleurodeles waltlii Frog, Xenopus laevis Frog, Rana perezi Toad, Bombian orientalis Salamaner, Necturus maculosus	[21,27,142,143,144,145,146,147]
	Thermosensitivity and chemosensitivity.	Toad, Bufo schneideri Frog, Lithobates catesbeianus	[100,101,105,106]
	Controlling the melanotrope cells during background adaptation.	Frog, Xenopus laevis	[26,148]
	Expression of nitric oxide synthase.	Frog, Xenopus laevis	[149]
Reptiles	Ascending and descending pathways.	Turtle, Pseudemys scripta elegans Lizard, Pogona vitticeps Snake, Python regius Snake, Python reticulatus Green iguana, Iguana iguana Lizard, Varanus exanthematicus Lizard, Gekko gecko	[22,24,25,29,150,151,152,153,154,155]
	Reduced chemosensitivity at higher temperatures.	Lizard, Varanus exanthematicus	[107]
	Projections to claustrum: regulating slow-wave sleep.	Lizard, Pogona vitticeps	[153]
	Identified the anatomical location and measured the soma size.	Lizard, Ctenosaura pectinata	[156]
Birds	Ascending and descending pathways.	Pigeon, Columba livia Chicken, Gallus gallus domesticus Duck, Anas platyrhinochos L. Zebra finch, Taeniopygia guttata	[31,32,33,36,37,38,61,157,158,159]
	Regulating song quality, song preference and song variability.	Zebra finch, Taeniopygia guttata	[34,123,124,125,127,160,161,162,163,164,165,166,167,168,169]
	The LC activates during mobbing behavior.	Crow, Corvus brachyrhynchos	[170]
	Development: origin and migration.	Chicken, Gallus gallus domesticus	[5,171]
	High expression of neurotropin receptors; uptake neurotophin directly through axons and indirectly through tanycytes.	Chicken, Gallus gallus domesticus	[86,87]
	Modulation on body temperature and sleep	Pigeon, Columba livia	[172]