the purpose of this study was to investigate the potential responses of the cardiovascular system and regional blood flow to hypoxic hypoxia (bb) and to carbon monoxide (co)-induced hypoxia (coh). ten anesthetized cats were studied under two nonnoxic (control: cont) and two hypoxic conditions. four types of radioactive micro spheres were used to measure regional blood flow during cont and two h...

This paper uses a steady-state modeling approach to describe the effects of changes in acid-base balance on the chemoreflex control of breathing. First, a mathematical model is presented, which describes the control of breathing by the respiratory chemoreflexes; equations express the dependence of pulmonary ventilation on Pco(2) and Po(2) at the central and peripheral chemoreceptors. These equa...

Our previous studies showed that decreased nitric oxide (NO) production enhanced carotid body (CB) chemoreceptor activity in chronic heart failure (CHF) rabbits. In the present study, we investigated the effects of neuronal NO synthase (nNOS) gene transfer on CB chemoreceptor activity in CHF rabbits. The nNOS protein expression and NO production were suppressed in CBs (P<0.05) of CHF rabbits, b...

Fish and amphibians utilise a suction/force pump to ventilate gills or lungs, with the respiratory muscles innervated by cranial nerves, while reptiles have a thoracic, aspiratory pump innervated by spinal nerves. However, fish can recruit a hypobranchial pump for active jaw occlusion during hypoxia, using feeding muscles innervated by anterior spinal nerves. This same pump is used to ventilate...

We developed an in vitro tadpole brainstem preparation in order to investigate the development of central respiratory chemoreception and rhythmogenesis. pH sensitive fluorescent dyes have been utilized to record intracellular pH (pHi) optically in central respiratory chemoreceptive regions in mammals. Our goal in this study was to develop the ability to record pHi optically while simultaneously...

Experiments were done to characterize the vascular responses to stimulation of aortic and carotid chemoreceptors and to identify the efferent components of the sympathetic system which are activated in different vascular beds. The chemoreceptors were stimulated with nicotine and cyanide in anesthetized and artificially ventilated dogs. The gracilis muscle and hindpaw were isolated and perfused ...

Animals use a variety of sensory modalities-including visual, acoustic, and chemical-to sense their environment and interact with both conspecifics and other species. Such communication is especially critical in eusocial insects such as honey bees and ants, where cooperation is critical for survival and reproductive success. Various classes of chemoreceptors have been hypothesized to play essen...

Both respiratory centres and the preganglionic vagal motoneurones, which control respiratory (striated) and airway (smooth) muscles respectively, receive information on the lungs, the circulation and the skeletal and respiratory muscles. Each of these nervous pathways has two components: one is phasic, i.e. in phase with biological rhythms, and comes from mechanoreceptors connected to large mye...

FITZGERALD, ROBERT S., JOAN TRACZ ZAJTCHUK, ROBERT W. B. PENMAN, AND JOHN F. PERKINS, JR. Ventilatory response to transient perfusion of carotid chemoreceptors. Am. J. Physiol. 207(6) : 1305-1313. I g64.-Properties of carotid chemoreceptors were evaluated in anesthetized dogs by measuring transient change in breath-by-breath minute ventilation (J?E) produced by brief (15-60 set) infusion into c...