Role of the vascular branch in the hemodynamic control of snakes at different temperatures.

• Grant number: 22/09159-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2023
• End date: January 31, 2024
• Field of knowledge: Biological Sciences - Physiology - Compared Physiology
• Principal Investigator: Cléo Alcantara Costa Leite
• Grantee: João Vítor Prado
• Host Institution: Centro de Ciências Biológicas e da Saúde (CCBS). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

Body temperature alterations (Tb) cause various changes in the physiology of all ectothermic animals, such as reptiles. Variations in metabolic demand and vascular responses compose some examples of it. The local control of capillary beds may generate either an increase or decrease in tissue perfusion according to the metabolic variations caused by temperature. Thus, to maintain an adequate supply of O2, the organism of these animals changes the systemic conductance. Squamates have a characteristic intracardiac blood shunt, and when Tb increases, there is an increase in systemic conductance. Therefore, it is also expected to have a higher R-L shunt. However, reduction in pulmonary perfusion caused by the increase of R-L shunt would result in hypoxemia, which is harmful when the metabolic demand is increased. In parallel, the opposite misadjustment would be expected when the temperature decreases. However, these responses are not observed, and reptiles are able to meet the changes in metabolic demand even facing the hemodynamic alteration caused by temperature change. The present investigation focuses on the vascular mechanisms that counterbalance these alterations are unknown. The complexity of the instrumentation required for such investigations makes it difficult to access this problem satisfactorily. Thus, in this project, we are using a new experimental model, the decerebrate rattlesnake, to investigate the vascular adjustments caused by temperature change over a wide temperature range (10°C, 20°C, and 30°C). This preparation has autonomic activity and allows the recording of multiple cardiovascular parameters concomitantly and without the deleterious effect of anesthetic agents or distress. We believe that the project will provide important information to understand vascular aspects of an important group in the history of vertebrate animals.