2014/11/22 by Leonida Fusani, Manfred Gahr · 20 citations
Agricultural and Biological Sciences · Biochemistry, Genetics and Molecular Biology · Environmental Science · Neuroscience · #Animal Behavior and Reproduction #Animal Vocal Communication and Behavior #Biology #Genetics #Marine animal studies overview #Melatonin #Melatonin receptor #Neuroscience #Receptor #Songbird #Zebra finch
paper · open access · doi:10.1159/000367984
published in Brain Behavior and Evolution 85(1), 4-14 (Karger Publishers)
openalex publication_date 2014/11/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/22
Previous autoradiography studies illustrated that several areas of the avian brain can bind the pineal hormone melatonin. In birds, there are three melatonin receptor (MelR) subtypes: MelIa, MelIb and MelIc. To date, their brain distribution has not been studied in any passerine bird. Therefore, we investigated mRNA distribution of MelR subtypes in adjacent sections of the brain of two songbirds, the blackcap and the zebra finch, in parallel with that of 2-[¹²⁵I]-iodomelatonin (IMEL) binding sites in the same brains. The general pattern of receptor expression shown by in situ hybridization of species-specific probes matched well with that of IMEL binding. However, the expression of the three subtypes was area specific with similar patterns in the two species. Some brain areas expressed only one receptor subtype, most brain regions co-expressed either MelIa with MelIb or MelIa with MelIc, whereas few areas expressed MelIb and MelIc or all three receptor subtypes. Since many sensory areas, most thalamic areas and subareas of the neopallium, a cortex analogue, express MelR, it is likely that most sensory motor integration functions are melatonin sensitive. Further, the area-specific expression patterns suggest that the regulatory role of melatonin differs among different brain areas. Since subareas of well-defined neural circuits, such as the visual system or the song control system, are equipped with different receptor types, we hypothesize a diversity of functions for melatonin in the control of sensory integration and behavior.