Dr. J. R. McNeill, PhD
Professor & Acting Head
Department of Pharmacology
College of Medicine
University of Saskatchewan
E-mail: robert.mcneill@usask.ca
Research Interests
My research program is devoted to the study of the role of peptide hormones—notably vasopressin, angiotensin, endothelin, ghrelin—in the regulation of the circulation at the hemodynamic level. Studies in animal models of hypertension and diabetes are a theme. Studies on the cardiovascular effects of natural products are an additional interest. In collaboration with others in the Group, new studies involve the role of gasotransmitters (e.g. NO, CO, H2S) and endothelium-dervided hyperolarizing factor (EDHF) in modulating the effects of these various peptide hormones.
Hemodynamic studies are performed using sophisticated state-of-the-art techniques. In conscious unrestrained rats, cardiac output and superior mesenteric arterial, renal, and hindquarter blood flows are recorded using ultrasonic transit-time flowmetry. These flow recordings together with recordings of blood pressure using radiotelemetry techniques allow the calculation of total and regional resistances to flow. In anesthetized rats, the resistance, fluid-exchange, and capacitance functions of the circulation are studied simultaneously by recording the integral of the difference between superior mesenteric arterial and venous flows.
The hemodynamic data generated from this work complements work at the cellular and molecular level by other investigators in our group and it provides an understanding at the whole animal integrative level. This collaborative work has generated novel findings on the contribution of endothelin to the vascular actions of vasopressin and angiotensin in rat models of hypertension and of NO in the regulation of skeletal muscle blood flow in response to exercise (swim training). Collaborative work on the roles of NO, CO and H2S in the regulation of the resistance, fluid-exhange, and capacitance functions of the circulation at the level of the whole animal are part of the GREAT initiative directed by R. Wang. Collaborative work on the relationship of ghrelin to EDHF at the whole animal level complements the work at the cellular level by V. Gopalakrishnan..
Keywords
hemodynamics; integrative whole animal; hypertension; diabetes; peptide
Selected Research Funding
MRC/CIHR: awarded each year from 1981—2005: “Endothelin in Hypertension”
HSF: awarded each year from 1972—2006: “Vasopressin in Hypertension
Publications
Ghosh M, Hanna ST, Wang R, McNeill JR. 2004. Altered vascular reactivity and KATP channel currents in vascular smooth muscle cells from deoxycorticosterone acetate (DOCA)-salt hypertensive rats. J Cardiovasc Pharmacol. 44 (5): 525-31.
Ghosh M, Wang HD, McNeill JR. 2004. Role of oxidative stress and nitric oxide in regulation of spontaneous tone in aorta of DOCA-salt hypertensive rats. British Journal of Pharmacology 141 (4) :562-73.
J. R. McNeill. (2003) Role of endothelin in the regulation of the resistance, fluid-exchange, and capacitance functions of the circulation. Can. J. Physiol. Pharmacol., 81: 522-532, review article.
Yu, M., M. Ghosh, and J. R. McNeill. (2003) A novel vasopressin peptide lowers blood pressure through decreases in cardiac output. Can. J. Physiol. Pharmacol., 81: 497-501, RAPID COMMUNICATION
Yu, M., V. Gopalakrishnan, T. W. Wilson, and J. R. McNeill. (2001) Endothelin antagonist reduces hemodynamic responses to vasopressin in DOCA-salt hypertension. Am. J. Physiol., 281: H2511-H2517.
Yu M., V. Gopalakrishnan and J.R. McNeill. 2001. Role of endothelin and vasopressin in DOCA-salt hypertension. Br. J. Pharmacol., 132:1447-1454.
R. Tatchum-Talom, R. Schulz, J.R. McNeill, and F. Khadour. (2000) Upregulation of neuronal nitric oxide synthase in skeletal muscle by swim training. Am. J. Physiol., 279(4):H1757-H1766.
R. Tatchum-Talom, V. Gopalakrishnan, and J.R. McNeill. (2000) Radiotelemetric monitoring of blood pressure and mesenteric arterial bed responsiveness in rats with STZ-induced diabetes. Can. J. Physiol. Pharmacol., 78:721-728.
R. Tatchum Talom , S.A. Judd, D.D. McIntosh, and J.R. McNeill. (1999) High Flax (linseed) diet restores endothelial function in the mesenteric arterial bed of spontaneously hypertensive rats. Life Sci., 64: 1415-1425.
McNeill, J.R. (1999) Interactions between herbal and conventional medicines.
Canadian J. Continuing Med. Edu., 11: 97-113.