Various clinical and pharmacological studies have indicated the cardioprotective role of Terminalia arjuna in cardiac ailments. The cardiovascular system is subject to precise reflex regulation so that an appropriate supply of oxygenated blood can be reliably provided to different body tissues under a wide range of circumstances. The sensory monitoring for this critical homeostatic process entails primarily mechanical (barosensory) information about pressure in the arterial system and, secondarily, chemical (chemosensory) information about the level of oxygen and carbon dioxide in the blood. The parasympathetic and sympathetic activity relevant to cardiovascular control is determined by the information supplied by these sensors.
The autonomic nervous system modulates beat-to-beat fluctuations in heart rate (HR). It modulates the electrical and contractile activity of the myocardium via the interplay of sympathetic and parasympathetic activity. Cardiovascular autonomic neuropathy, a common form of autonomic dysfunction, causes abnormalities in heart rate control, as well as defects in central and peripheral vascular dynamics. Methods to quantify HR and blood pressure variability have been evaluated as indicators of sympathetic and parasympathetic modulation of the cardiovascular system in humans and in experimental models. These methods seemed to detect early autonomic dysfunction at a time when other metabolic dysfunctional changes were not clearly observed. Baroreflex sensitivity and Heart rate variability are the two frequently used parameters to assess autonomic control of cardiovascular functions. Baroreflex sensitivity.
The evaluation of baroreflex sensitivity (BRS) is an established tool for the assessment of autonomic control of the cardiovascular system. Arterial baroreceptors provide the central nervous system with a continuous stream of information on changes in blood pressure (which are sensed by the stretch receptors in the wall of the carotid sinuses and aortic arch), on the basis of which efferent autonomic neural activity is dynamically modulated. Activation of arterial baroreceptors by a rise in systemic arterial pressure leads to an increase of the discharge of vagal cardioinhibitory neurons and a decrease in the discharge of sympathetic neurons both to the heart and peripheral blood vessels. This result in bradycardia decreased cardiac contractility and decreased peripheral vascular resistance.