Melatonin receptors and signal transduction in melatonin-sensitive and melatonin-insensitive populations of white-footed mice (Peromyscus leucopus).
The pineal hormone melatonin times seasonal alterations in reproductive function in photoperiodic mammals. In white-footed mice, there is variation in responsiveness to the reproductive effects of melatonin between populations originating in different locations; mice from Connecticut (CT) respond normally to melatonin, while mice from Georgia (GA) appear insensitive to melatonin. In the present paper, we compare melatonin receptor distribution and a second messenger response to melatonin in white-footed mice from CT and GA. Specific binding of 125I-labeled melatonin (I-MEL) was observed in a variety of brain regions in each population, but there were no consistent differences in the distribution or intensity of I-MEL binding between the populations. Furthermore, melatonin inhibited forskolin-stimulated cAMP accumulation in median eminence/pars tuberalis explants from both populations. These results suggest that insensitivity to melatonin in GA mice is not due to a gross defect in melatonin receptors or receptor-effector coupling.
Weaver
D R
DR
Laboratory of Developmental Chronobiology, Children's Service, Massachusetts General Hospital, Boston 02114.
Carlson
L L
LL
Reppert
S M
SM
D000818:Animals; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D010542:Peromyscus / Q000378:metabolism* / Q000502:physiology; D044094:Receptors, Melatonin; D017981:Receptors, Neurotransmitter / Q000187:drug effects / Q000502:physiology*; D015398:Signal Transduction
D044094:Receptors, Melatonin; D017981:Receptors, Neurotransmitter; D008550:Melatonin