Blocking synaptic transmission with tetanus toxin light chain reveals modes of neurotransmission in the PDF-positive circadian clock neurons of Drosophila melanogaster

Blocking synaptic transmission in PDF-positive neurons results in complex circadian rhythms in Drosophila melanogaster.

• Approximately 150 clock neurons govern circadian locomotor rhythms in fruit flies, classified into seven groups.
• Neurons expressing pigment-dispersing factor (PDF) are crucial for organizing the circadian pacemaking system.
• Transgenic flies with blocked chemical synaptic transmission in PDF-positive neurons exhibit a free-running rhythm similar to wild-type flies under constant darkness.
• Under constant light conditions, these transgenic flies display complex rhythms with both short and long period components.
• The unknown neurotransmitter (UNT) may be involved in synaptic transmission within the clock network, potentially contributing to arrhythmicity under constant light.
• Phase separation of TIMELESS (TIM) cycling is induced in some clock neurons when exposed to constant light.

AI simplified