Proctolin (CAS 57966-42-4)

Proctolin is a neuropeptide consisting of a sequence of five amino acids (Arg-Tyr-Leu-Pro-Thr) and is known for its role as a neuromodulator and neurotransmitter in various invertebrates, particularly insects. Initially isolated from the cockroach Periplaneta americana, proctolin is involved in the modulation of muscle contraction and the regulation of rhythmic motor patterns, such as those required for walking, flight, and gut peristalsis. The peptide exerts its effects by binding to specific G-protein coupled receptors on the cell surfaces, leading to an increase in intracellular calcium levels which are crucial for muscle contraction. In research contexts, proctolin has been extensively utilized to study neuromuscular transmission and the broader physiological processes governed by neuropeptides in invertebrates. Its application has helped delineate the complex pathways of neuromodulation, revealing insights into how neuromodulators influence the activity of neural circuits responsible for specific and vital behaviors. The study of proctolin and its receptors has also provided a comparative basis for understanding similar mechanisms in vertebrates, thereby enhancing our grasp of fundamental neurobiological processes across different species. This peptide has thus been instrumental not only in entomological research but also in broader biological inquiries into neuromodulatory systems.