The reduction in arterial pH with increased temperature is not affected by hyperoxia in toads (Rhinella marina) and pythons (Python molurus).

It is well established that arterial pH decreases with increased temperature in amphibians and reptiles through an elevation of arterial PCO2, but the underlying regulation remains controversial. The alphastat hypothesis ascribes the pH fall to a ventilatory regulation of protein ionisation, but the pH reduction with temperature is lower than predicted by the pKa change of the imidazole group on histidine. We hypothesised that arterial pH decreases at high, but not at low, temperatures when toads (Rhinella marina) and snakes (Python molurus) are exposed to hyperoxia.

Adrenergic control of functional characteristics of the cardiovascular system in the South American rattlesnake, Crotalus durissus.

In squamate reptiles, extensive innervation of the heart and vascular beds allows for continuous modulation of the cardiovascular system by the autonomic nervous system. The systemic vasculature is the main target of excitatory sympathetic adrenergic fibers, while the pulmonary circulation has been described as less responsive to both nervous and humoral modulators. However, histochemical evidence has demonstrated the presence of adrenergic fibers in pulmonary circulation.

Role of Nitric Oxide in the Cardiovascular System of South American Rattlesnakes ().

AbstractUnderstanding the basis of vascular tonus regulation is fundamental to comprehending cardiovascular physiology. In the present study, we used the recently developed decerebrate rattlesnake preparation to investigate the role of nitric oxide (NO) in the control of vascular tonus in a squamate reptile. This preparation allowed multiple concomitant cardiovascular parameters to be monitored, while avoiding the deleterious effect of anesthetic drugs on autonomic modulation.

A Decerebrate Preparation of the Rattlesnake, , Provides an Experimental Model for Study of Autonomic Modulation of the Cardiovascular System in Reptiles.

AbstractThe South American rattlesnake, , has been successfully used as an experimental model to study control of the cardiovascular system in squamate reptiles. Recent technical advances, including equipment miniaturization, have lessened the impact of instrumentation on in vivo recordings, and an increased range of anesthetic drugs has improved recording conditions for in situ preparations. Nevertheless, any animal-based experimental approach has to manage limitations regarding the avoidance of pain and stress the stability of the preparation and duration of experiments and the potentially overriding effects of anesthesia.

Hypotensive effect of Eugenia dysenterica leaf extract is primarily related to its vascular action: The possible underlying mechanisms.

Ethnopharmacological Relevance: Eugenia dysenterica (ED) leaves are used in Brazil to treat cardiac diseases; however, there are no scientific data describing the effects of this species on cardiac activity.

Aim Of The Study: To investigate the effect of ED aqueous leaf extract (EDLE) on hear rate (HR) and mean arterial pressure (MAP) of anaesthetised rats and its underlying mechanism of action.

Material And Methods: EDLE was analysed, and its proanthocyanidin composition was determined.