Professor of Physiology
Dr. St. John received his undergraduate degree in Biology from Brown University in Providence, Rhode Island. Graduate study was performed at the University of North Carolina in Chapel Hill from which a Ph.D. degree in Physiology was obtained in 1970. Post-doctoral training was obtained in the laboratories of S.C. Wang in the Department of Pharmacology at the College of Physicians and Surgeons of Columbia University in New York. In addition, a sabbatical year was spent in the laboratory of Armand L. Bianchi at the University of Aix-Marseille in Marseille, France. Presently, several months each year are spent in the laboratory of Julian F.R. Paton at the University of Bristol, England. Dr. St. John has been on the faculty of Dartmouth Medical School since 1976 and is presently Professor of Physiology.
It has long been recognized that normal ventilatory activity can be supported by the brainstem portion of the central nervous system. There are several interrelated questions concerning this ventilatory activity.
- First, what are the neurophysiological mechanisms which are responsible for its genesis?
- Second, how do activities of various groups of neurons combine to produce the respiratory-modulated discharge patterns of cranial and spinal nerves?
- Third, how do reflexes involving chemoreceptors and mechanoreceptors produce alterations in these neural and neuronal activities?
In a series of experiments in this laboratory, it has been demonstrated that there are multiple sites within both the pontile and medullary portions of the brainstem from which a ventilatory rhythm may be generated. Present examinations include determinations of which site is critical for the genesis of the normal respiratory rhythm of eupnea. Also, the possibility is being explored that the discharge of pacemaker neurons underlies the commencement of ventilatory activity.
St.-John, W.M. and I.A. Rybak. Influence of levels of carbon dioxide and oxygen upon gasping in perfused rat preparation. Respiration Physiology 129: 279-287, 2002.
Rybak, I. A, J.F.R. Paton, R.F. Rogers and W.M. St.-John Generation of the respiratory rhythm: state-dependency and switching. Neurocomputing, 44-46: 605-614, 2002.
St.-John, W.M. and J.F.R. Paton. Neurogenesis of gasping does not require inhibitory transmission using GABAA or glycine receptors. Respiratory Physiology and Neurobiology 132: 265-277, 2002.
St.-John, W.M., I. Rybak and J.F.R. Paton. Potential switch from eupnea to fictive gasping after blockade of glycine transmission and potassium channels. American Journal of Physiology 283: R721-731, 2002.
St.-John, W.M. and J.C. Leiter. Gasping is elicited by briefer hypoxia or ischemia following blockade of glycinergic transmission. Respiratory Physiology and Neurobiology 133: 167-171, 2002.
St.-John, W.M. Gasping. In: Respiratory Control and its Disorders in the Newborn. Lung Biology in Health and Diseases, O. Matthew (editor), Marcel Dekker, Inc., pp 17-38, 2003.Harris, M.B. and W.M. St.-John. Pulmonary stretch receptor feedback modulates both eupnea and gasping in the perfused rat preparation. American Journal of Physiology 285: R215-221, 2003.
St.-John, W.M. and J.F.R. Paton. Respiratory-modulated neuronal activities of the rostral medulla which may generate gasping. Respiratory Physiology and Neurobiology 135: 97-101, 2003.
St.-Jacques, R., J.J. Filiano, R.A. Darnall and W.M. St.-John. Characterization of hypoxia-induced ventilatory depression in newborn piglets. Experimental Physiology 88: 505-515, 2003
St.-John, W.M. and J.C. Leiter. High frequency oscillations of phrenic activity in eupnea and gasping: influence of temperature of in situ rat. American Journal of Physiology 285: R404-R412, 2003.
Rybak, I.A., N.A. Shevtsova, W.M. St.-John, J.F.R. Paton and O. Pierrefiche. Endogenous rhythm generation in the pre-Bötzinger Complex and ionic currents: Modelling and in vitro studies. European Journal of Neurosciences 18: 239-257, 2003.
St.-John, W.M. Gasping. In: Respiratory Control and its Disorders in the Newborn. Lung Biology in Health and Diseases, O. Matthew (editor), Marcel Dekker, Inc., pp 17-38, 2003.
St.-John, W.M. and J.F.R. Paton. Defining Eupnea. Respiratory Physiology and Neurobiology (in press), 2003.