We have just published with Elia Ciani, a PhD student that I am co-supervising, and other members of the team as well as important collaborators in the laboratory of Prof. Bertha Levavi-Sivan, a paper in Journal of Pineal Research (Impact Factor 15).
The article is entitled “Melatonin receptors in Atlantic salmon stimulate cAMP levels in heterologous cell lines and show season‐dependent daily variations in pituitary expression levels“.
The hormone melatonin connects environmental cues, such as photoperiod and temperature, with a number of physiological and behavioural processes, including seasonal reproduction, through binding to their cognate receptors.
This study reports the structural, functional and physiological characterization of five high‐affinity melatonin receptors (Mtnr1aaα, Mtnr1aaβ, Mtnr1ab, Mtnr1al, Mtnr1b) in Atlantic salmon. Contrary to previous studies in vertebrates, pharmacological characterization of four receptors in COS‐7, CHO and SH‐SY5Y cell lines (Mtnr1Aaα, Mtnr1Aaβ, Mtnr1Ab, Mtnr1B) showed induction of intracellular cAMP levels following 2‐iodomelatonin or melatonin exposure.
We also show that pituitary receptors displayed daily fluctuations in mRNA levels during spring, prior to the onset of gonadal maturation, but not in autumn, strongly implying a direct involvement of melatonin in seasonal processes regulated by the pituitary.
Publication in the Journal of Pineal Research, doi 10.1111/jpi.12590