Table 2 Association of EP/CCHamide peptidergic signaling based on expression, peptide detection and functional analysis of previous studies

Annelida

Eisenia foetida, Pheretima vittata

Isolation of EP from gut tissue as well as whole bodies and excitation of gut tissue by EP application.

[6]

Hirudo nipponia,

Excitation of the crop gizzard by EP application.

[7]

Eisenia foetida

EP binding capacity is high in anterior part of digestive tract and the nephridia.

[9]

Whitmania pigra

EP immunoreactivity in supra-esophageal ganglion, circum-esophageal connective, sex segmental ganglion.

[8]

Perinereis vancaurica

EP immunoreactivity in CNS, epithelial cells of pharynx and epidermal cells.

[10]

Mollusca

Thais clavigera

Excitation of esophagus and penial complex by EP application, EP immunoreactivity in CNS and nerve endings of the penial complex.

[15]

Thais clavigera

EP1 expression in sub-esophageal, pleural, pedal and visceral ganglion and EP2 expression in pedal and visceral ganglion.

[16]

Hexapoda

Bombyx mori - larvae

CCHa expression in the central nervous system and the midgut.

[23]

Phormia regina - adults

CCHa2 injection stimulates feeding motivation (measured by the proboscis extension reflex at different sugar concentrations).

[5]

Delia radicum - larvae

CCHa1 was exclusively detected in the gut.

[41]

Spodoptera exigua - larvae

CCHa1 and CCHa2 are expressed in the larval gut and brain. Starvation increased CCHa1 expression in larvae.

[39]

Drosohila melanogaster - larvae & adults

High CCHa2 expression in gut and low expression in brain; high CCHa2 receptor expression in brain and low expression in gut.

[40]

D. melanogaster - adults

Upregulation of CCHa (1?) in the brain of starved animals. RNAi knockdown of the CCHa1 receptor and CCHa1 receptor mutants showed an abolishment of a starvation-induced increase in olfactory responsiveness.

[36]

D. melanogaster - larvae & adults

Distinct CCHa1 and CCHa2 immunoreactivity in the digestive tract in both larvae and adults.

[42]

D. melanogaster - larvae

CCHa2 is highly expressed in fat body and slightly in gut, CCHa2 receptor is expressed in few endocrine cells in the brain including insulin like peptide (ILP) 2 producing cells. Starvation reduces CCHa2 expression. CCHa2 receptor mutants showed no change in ILP 2 and 3 expression but reduced ILP 5 expression. CCHa2 mutants show growth retardation and developmental delay. CCHa2 mutants show reduced ILP 5 expression and reduced body weight.

[38]

D. melanogaster - larvae & adults

Larvae: CCHa2 mutants show reduced feeding rate/activity and have a delayed development. Larvae and Pupae have reduced expression of insulin like peptide 2 and 3. CCHa2 is highly expressed in gut and slightly in brain. No effect detected for CCHa1.

Adults: CCHa2 mutants show reduced feeding and reduced locomotory activity. No effect detected for CCHa1.

[37]

Crustacea

Marsupenaeus japonicus – juvenile/adults

Highest expression of CCHa in ventral nerve cord, brain, eyestalks and gills, only low expression in intestines and stomach tissue. No effect of starvation on CCHa expression.

[43]

Nephrops norvegicus - adults

Tissue specific transcriptome detection of two CCHa’s in brain, thoracic ganglia and eyestalks, but not in hepatopancreas or ovaries.

[26]