The overall goal of this proposed research is to investigate the control of peripheral vascular resistance in conscious neonatal lambs. The studies include 1) the definition of dose response relationships of phenylephrine (representative of alpha1- adrenergic stimulation), angiotensin II and vasopressin infused into the hind limbs of newborn lambs to femoral arterial blood flow in that limb; 2) the development of the model of local receptor blockade in the hind limb of the newborn lamb, focusing on the alpha1, vasopressin (V1) and angiotensin II receptors; 3) the determination of the hemodynamic and endocrine changes that occur in lambs in response to different degrees of blood loss; 4) the evaluation of the relative roles of receptors in the development of vascular resistance during hemorrhage by bleeding the animals during regional blockade. Chronically cannulated newborn lambs are chosen for the project because it is possible to study the cardiovascular and endocrine relationships in these animals in the absence of the physiologic changes brought about by surgery and anesthesia. The research will further knowledge on the control of peripheral vascular resistance by endocrine reflexes. Hypotension of various causes is a frequent clinical problem facing human newborns. Increased understanding of the adaptive mechanisms used by neonates in response to hypotension may prove important in the development of management strategies for the premature infant or the term infant with hypotension.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
5R29HD023847-05
Application #
3469772
Study Section
Experimental Cardiovascular Sciences Study Section (ECS)
Project Start
1988-02-01
Project End
1994-01-31
Budget Start
1992-02-01
Budget End
1994-01-31
Support Year
5
Fiscal Year
1992
Total Cost
Indirect Cost
Name
Wake Forest University Health Sciences
Department
Type
Schools of Medicine
DUNS #
041418799
City
Winston-Salem
State
NC
Country
United States
Zip Code
27106
Eisenach, J C; Tong, C; Stump, D A et al. (1992) Vasopressin and fetal cerebrovascular regulation. Am J Physiol 263:R376-81
Block, S M; Barnes, K D; Zoltoski, R (1991) Central alpha-1-adrenergic control of vasopressin secretion in newborn lambs. Pediatr Res 30:50-4