Pigment‐dispersing hormone‐immunoreactive neurons in the nervous system of wild‐type Drosophila melanogaster and of several mutants with altered circadian rhythmicity

Eight PDH-immunoreactive neurons were identified at the anterior base of the medulla in wild-type and rhythmic mutant Drosophila melanogaster.

• Four large PDFMe neurons have extensive branching patterns in the medulla and project axons to the opposite medulla.
• Four smaller PDFMe neurons extend fibers in the median protocerebrum, near other PDH-immunoreactive neurons.
• The PDFMe neurons may be involved in the circadian pacemaking system of Drosophila.
• Their size and location match those of neurons containing a protein critical for maintaining circadian rhythms.
• Alterations in the branching of PDFMe neurons in specific mutants could explain disrupted locomotor rhythms.
• In the arrhythmic mutant disconnected, PDFMe neurons are absent, while the per0 mutant retains normal PDH immunoreactivity.

AI simplified