Meeting Abstract
The developing heart is a sensitive indicator of the effects of environmental stressors such as polyaromatic hydrocarbons (PAHs), a class of ubiquitous environmental contaminants. Resulting changes in morphology, edema, arrhythmias and heart rate changes and disruptions to cardiac output are common endpoints that can be measured optically, providing a general overview of cardiac performance and indices of effect. Indeed, these endpoints have become a cornerstone for assessing the effects of PAH toxicity in vertebrate species. Determination of blood pressure requires physical intervention, but reveals fine-scale physiological patterns of hemodynamic performance. Servonull pressure systems are capable of recording pressures in micron-sized chambers, such as the embryonic fish heart. Cardiac function of the red drum (Sciaenops ocellatus) and the Gulf killifish ( Fundulus grandis) were assessed through larval and juvenile stages to compare altricial and precocial modes of development following exposure to PAHs. Development of blood pressure with respect to heart rate and cardiac output revealed patterns of heart function that correlated with mode of development and functional constraints imposed by developmental timing (e.g. onset of gill function, swimming, feeding, etc.) Alterations in blood pressure associated with exposure to the toxicants were more closely related to an overall delay in development than directly to the stressor. These studies demonstrate the use of fine scale physiologic measures to assess the functional role of the cardiovascular system in the teratogenicity of PAHs, and the ontogeny of cardiovascular function in two emerging aquatic model species.
