Cephalic stimulation of pre-absorptive protein synthesis in Burmese pythons.

Digestion is initiated not only by the presence of nutrients in the gastrointestinal tract but also by anticipatory mechanisms collectively termed the cephalic phase. While this feed-forward regulation is well documented in mammals, its physiological significance in ectothermic vertebrates remains poorly understood. We demonstrate that Burmese pythons (Python bivittatus) exhibited a robust stimulation of protein synthesis in skeletal muscle in response to mock feeding where snakes were allowed to strike and constrict prey without ingestion. We also provide compelling evidence for similar stimulation in the stomach and intestinal mucosa. This cephalic response resembles the pre-absorptive rise in protein synthesis during voluntary ingestion. Notably, this response was independent of physical activity, as simulated prey constriction alone did not elevate protein synthesis. In pancreatectomised snakes, the response in skeletal muscle was markedly reduced, implicating pancreatic secretions in this regulation. Our findings highlight the metabolic significance of the cephalic phase in reptiles, initiating protein turnover in the skeletal muscle before nutrient assimilation, and underscore the broader relevance of anticipatory regulation in vertebrate digestion.