93015308 Tasker The hypothalamus is the brain structure that through its link with the pituitary gland, is responsible for controlling most of the organism's basic reproductive and homeostatic functions. Pituitary hormones are released into the blood circulation on command from the hypothalamus and are carried to endocrine and muscle targets, where they cause steroid secretion or muscle contraction. As might be expected from the wide range of functions of pituitary hormones, there is a diversity of hormone- secreting systems in the hypothalamus, each activated under different conditions and with different release profiles. Dr. Tasker is interested in determining whether the distinct hypothalamic secretory systems interact to alter one another's secretion. For example, the hormone systems responsible for lactation and for the body's stress response are both located in the paraventricular nucleus of the hypothalamus. Empirical evidence points to an interaction between these two systems since emotional stress can suppress a mother's ability to provide milk to her young, and breast feeding provided the mother with a temporary feeling of calm and well being. Dr. Tasker will employ electrophysiological and neuroanatomical technique to examine integrative interactions among two subpopulations of neurons located within the hypothalamic paraventricular nucleus. By combining the simultaneous intracellular and whole-cell patch- clamp recordings, intracellular dye injection and immunohistochemical, he will detect synaptic intercommunication between neurons that synthesize and release different hormones. These findings will provide new insights about the basic functioning of the hypothalamus. In addition, knowledge about the interdependence of neurosecretory functions and behavior will increase our understanding of how seemingly disparate physiological responses of the body influence one another. ***
