Willis K. Samson, Ph.D. » Investigators

Cardiovascular Research Interests:

Primary area of research:

• Neuropeptides and the control of cardiovascular function and stress hormone secretion

Related areas of research:

• Discovery of novel peptide hormones and characterization of their cognate receptors in cardiovascular and autonomic tissues

Summary of cardiovascular research:

We study the roles played by vasoactive peptides in the coordinated regulation of cardiovascular homeostasis. Cardiovascular homeostasis (health) is maintained by hormonal and neuronal mechanisms, which are all integrated to assure adequate cardiac function. This homeostasis requires communication among numerous tissues (e.g., blood vessels, kidneys, adrenal glands, brain, and the heart itself) and it has become clear that these organ systems are not only interconnected via nerves, but also that a blood-borne system of messengers (i.e., hormones) acts to coordinate their function. These hormones are actually small proteins that are produced in many tissues, most notably the blood vessels themselves, the heart, and even the brain, where they function as neurotransmitters.

Our particular focus is how these vasoactive peptides act in brain (as neurotransmitters) and in the anterior pituitary gland (controlling the release of classical hormones) so that cardiovascular and renal function is maintained. In particular, we are interested in how our bodies regulate fluid and electrolyte intake and excretion. Volume status and plasma osmolality are factors that can seriously compromise cardiac function. We study how these small peptides act in brain to control salt and water intake and how they modify autonomic nervous system function (which then controls blood pressure).

We are studying the actions of three classes of known peptides in brain and pituitary gland: the adrenomedullins, the hypocretins/orexins, and the prolactin releasing peptides. We are also characterizing two peptide hormones, nesfatin (discovered by M. Mori) and neuronostatin (discovered by our lab) in terms of their CNS and direct cardiac actions to control circulatory function. What these peptides have in common is the ability to alter cardiac performance by actions in brain. We study those actions of these peptides in vivo and in a tissue culture system in vitro, employing both classical pharmacologic approaches and more modern molecular technologies. Our long term goals are to understand the relevance of the actions of these peptides in brain and heart and to establish the potential for their use in clinical settings.