Neuropeptide PDF plays multiple roles in the circadian clock of Drosophila melanogaster

摘要

The neuropeptide pigment-dispersing factor (PDF) of Drosophila melanogaster (D. melanogaster) belongs to the family of p-pigment-dispersing hormones (p-PDHs) originally isolated from crustaceans. p-PDHs may be involved in the circadian clocks of all arthropods, whereby the strongest evidence for such a role comes from the fruit fly D. melanogaster. Only eight neurons per brain hemisphere contain PDF in the adult fly brain. Four neurons have small somata (s-LN_v), express non-amidated PDF, secrete PDF rhythmically into the dorsal protocerebrum, and are particularly important for rhythmic locomotor activity under constant dark conditions. The other four neurons have large somata (s-LN_v), express amidated PDF, do not oscillate under constant conditions, connect the s-LN_v of both brain hemispheres, strongly influence the oscillations of the s-LN_v, and mediate light-input to the circadian system. Overall, PDF represents a crucial factor in the clock of D. melanogaster. The functional similarity of PDF with the mammalian neuropeptide vasoactive intestinal polypeptide (VIP) is discussed.