The pancreas does not contribute to the non-adrenergic-non-cholinergic stimulation of heart rate in digesting pythons

• Published in: Comparative biochemistry and physiology. Part A, Molecular & integrative physiology Molecular & integrative physiology, 2024-05, Vol.291, p.111608-111608, Article 111608
• Main Authors: Guagnoni, Igor Noll, Last, Katja Bundgaard, Rindom, Emil, Wang, Tobias
• Format: Article
• Language: English
• Subjects: Animals; Boidae - physiology; Digestion; Glucagon; Heart rate; Heart Rate - physiology; Hormones - metabolism; Insulin; NANC; Pancreas; Python bivittatus; Reptile; Snakes; Tachycardia; Vertebrates
• ISSN: 1095-6433; 1531-4332
• DOI: 10.1016/j.cbpa.2024.111608

Vertebrates elevate heart rate when metabolism increases during digestion. Part of this tachycardia is due to a non-adrenergic-non-cholinergic (NANC) stimulation of the cardiac pacemaker, and it has been suggested these NANC factors are circulating hormones that are released from either gastrointestinal or endocrine glands. The NANC stimulation is particularly pronounced in species with large metabolic responses to digestion, such as reptiles. To investigate the possibility that the pancreas may release hormones that exert positive chronotropic effects on the digesting Burmese python heart, a species with very large postprandial changes in heart rate and oxygen uptake, we evaluate how pancreatectomy affects postprandial heart rate before and after autonomic blockade of the muscarinic and the beta-adrenergic receptors. We also measured the rates of oxygen consumption and evaluated the short-term control of the heart using the spectral analysis of heart rate variability and the baroreflex sequence method. Digestion caused the ubiquitous tachycardia, but the intrinsic heart rate (revealed after the combination of atropine and propranolol) was not affected by pancreatectomy and therefore hormones, such as glucagon and insulin, do not appear to contribute to the regulation of heart rate during digestion in Burmese pythons. [Display omitted] •NANC factors stimulates heart rate in digestion.•Pancreatic hormones may exert a positive chronotropic effect on the heart.•Removal of the pancreas does not affect the intrinsic heart in digesting pythons.•Pancreatic hormones are not involved in NANC stimulation in the postprandial tachycardia in pythons.