Melanocortin 4 receptor becomes an ACTH receptor by coexpression of melanocortin receptor accessory protein 2.

Melanocortin 2 receptor (MC2R) is the only canonical ACTH receptor. Its functional expression requires the presence of an accessory protein, known as melanocortin receptor 2 accessory protein 1 (MRAP1). The vertebrate genome exhibits a paralogue gene called MRAP2, which is duplicated in zebrafish (MRAP2a and MRAP2b), although its function remains unknown.

Effects of dopaminergic system activation on feeding behavior and growth performance of the sea bass (Dicentrarchus labrax): a self-feeding approach.

Dopamine is synthesized from l-dopa and subsequently processed into norepinephrine and epinephrine. Any excess neurotransmitter can be taken up again by the neurons to be broken down enzymatically into DOPAC. The effect of dopamine on mammalian food intake is controversial.

Molecular characterization and functional regulation of melanocortin 2 receptor (MC2R) in the sea bass. A putative role in the adaptation to stress.

The activation of melanocortin 2 receptor (MC2R) by ACTH mediates the signaling cascade leading to steroid synthesis in the interrenal tissue (analogous to the adrenal cortex in mammals) of fish. However, little is known about the functional regulation of this receptor in fish. In this work described, we cloned sea bass MC2R from a liver cDNA.

Stress-induced effects on feeding behavior and growth performance of the sea bass (Dicentrarchus labrax): a self-feeding approach.

Repetitive aquaculture-related protocols may act as cyclic stressors that induce chronic stress in cultured fish. The sea bass is particularly sensitive to stressful conditions and the mere presence of humans will disturb feeding behavior. In this paper, we study whether chronic stress induced by repetition of acute stress protocols affects long-term feeding behavior and growth performance in sea bass and whether exogenous cortisol may induce stress-like changes in these parameters.

Effects of cyclic hydrostatic pressure on the brain biogenic amines concentrations in the flounder, Platichthys flesus.

The present study evaluated the effects of cyclic variations of hydrostatic pressure (HP) on neurotransmitters in the whole brain of flounder. The concentrations of the biogenic amines L-3,4-dihydroxyphenylalanine (L-DOPA), dopamine (DA), norepinephrine (NE), epinephrine (E), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), 3-methoxytyramine (3-MT), 5-hydroxytryptamine (5-HT) and 5-hydroxyindolacetic acid (5-HIAA) were measured. Fish were subjected to HP cyclic variations which mimic naturally occurring conditions for a period of 14 days.

Evidence for arylalkylamine N-acetyltransferase (AANAT2) expression in rainbow trout peripheral tissues with emphasis in the gastrointestinal tract.

In fish, melatonin is reported to be produced mainly in the pineal organ, but there is also evidence for the presence of melatonin in a number of extrapineal sites where it could act as an intracellular mediator or paracrine signal. The present study use the reverse transcription-polymerase chain reaction (RT-PCR) to evaluate the expression of the enzyme arylalkylamine-N-acetyltransferase (AANAT2), which catalyzes the limiting step for melatonin synthesis, in different peripheral tissues of rainbow trout, with emphasis in the gastrointestinal tract (GIT). The results show AANAT2 gene expression in almost all peripheral tissues tested, including gills, kidney, muscle, skin, liver, Brockmann bodies, gall bladder, spleen and GIT, but not in adipose tissue.

Daily changes in parameters of energy metabolism in brain of rainbow trout: dependence on feeding.

We assessed the daily patterns of parameters involved in energy metabolism in plasma and brain of rainbow trout. Where daily rhythms were found, we analyzed the potential influence of feeding. Immature rainbow trout were randomly distributed in 3 groups: fish fed for 7 days, fish fasted for 7 days, and fish fasted for 7 days and refed for 4 days.