Professor, Department of Physiology & Pharmacology
Cumming School of Medicine
Room 272A, Heritage Medical Research Buiding
3330 Hospital Drive NW.
Calgary AB T2N 4N1
Research Interests and Projects:
Regulation of renal function
There are numerous differences in the function of the kidney at birth compared to later in life. For example, glomerular perfusion is reduced, proximal tubular Na+ reabsorption is enhanced, and the concentrating capacity of the kidney is decreased.
In on-going studies, we are evaluating the effects of various neurohumoral factors such as renal sympathetic nerves, angiotensin II and nitric oxide in modulating various parameters of glomerular and tubular function in the newborn period and during postnatal maturation.
Regulation of renal vascular resistance
The vascular resistance of the kidney is elevated at birth and decreases during postnatal maturation. Despite much investigation into the possible neurohumoral factors modulating renal vascular resistance during development, the underlying mechanisms remain elusive.
In previous studies, we have evaluated the effects of the endogenously produced dilator agents bradykinin and nitric oxide, as well as the constrictor effects of angiotensin II and renal sympathetic nerves, on renal vascular tone.
In future experiments, we will further evaluate the vasoconstrictor effects of endothelin and its interaction with the vasodilator nitric oxide in modulating renal vascular tone during ontogeny.
Physiological responses to furosemide
In previous studies we have shown that some of the endocrine and cardiovascular responses to furosemide administration are developmentally regulated.
In studies designed to further evaluate the physiological responses to furosemide during postnatal maturation, the arterial baroreceptor reflex control of heart rate is assessed before and after furosemide administration.
In additional experiments, the potential interactions of arginine vasopressin and angiotensin II on the cardiovascular responses to furosemide will be investigated.
Physiological responses to haemorrhage
We have previously demonstrated that some of the endocrine and cardiovascular responses to non-hypotensive and hypotensive haemorrhage are developmentally regulated. To date, however, the role of the kidney in the adaptations to haemorrhage during postnatal life is not known.
In studies designed to further evaluate the renal responses to haemorrhage during postnatal maturation, various parameters of renal function will be measured before and after haemorrhage at different stages of development.
In additional experiments, the potential interactions of endogenous opioids and arginine vasopressin on the renal responses to haemorrhage will be investigated.
Factors modulating the arterial baroreceptor reflex
Recently, we have demonstrated that there are considerable differences in the parameters governing the arterial baroreceptor reflex during the newborn period as compared to later in life. In addition, we have shown that these developmental differences are removed in the absence of endogenously produced nitric oxide.
In on-going experiments, we will further evaluate potential factors -- including angiotensin II and arginine vasopressin -- in modulating the arterial baroreflex during ontogeny.
Developmental physiology with emphasis on the kidney and blood pressure regulation during the newborn period