Galanin is present in neurons in the brain that are important in the control of arterial pressure, and intracisternal administration of galanin evokes hypotension, but the site of action is unknown. In urethane-anesthetized, vagotomized mechanically ventilated Sprague-Dawley rats (n = 34), we investigated the effects of microinjecting galanin (1 mM, 50 nl, 50 pmol) into the rostral ventrolatera...

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 an...

Obstructive sleep apnea (OSA) is a common disorder of upper airway obstruction during sleep. The effects of intermittent upper airway obstruction include alveolar hypoventilation, altered arterial blood gases and acid-base status, and stimulation of the arterial chemoreceptors, which leads to frequent arousals. These arousals disturb sleep architecture and cause hypersomnolence. Chronic intermi...

Animal studies have demonstrated that activation of the baroreflex by increases in arterial pressure inhibits cardiovascular and ventilatory responses to activation of peripheral chemoreceptors (PC) with hypoxia. In this study, we examined the influences of baroreflex activation on the sympathetic response to stimulation of PC and central chemoreceptors in humans. PC were stimulated by hypoxia ...

Alveolar partial pressure of carbon dioxide (PACO2) and alveolar partial pressure of oxygen (PAO2) oscillate at the frequency of respiration and the oscillations persist into the arterial blood as oscillations of arterial partial pressure of carbon dioxide (PaCO2) and arterial partial pressure of oxygen (PaO2). Arterial chemoreceptors respond quickly enough to changes in PaCO2 and PaO2 for the ...

The purpose of the present investigation was to examine the contribution of the carotid body chemoreceptors to changes in baroreflex control of heart rate with exposure to hypoxia. We hypothesized spontaneous cardiac baroreflex sensitivity (scBRS) would be reduced with hypoxia and this effect would be blunted when carotid chemoreceptor activity was reduced with low-dose dopamine. Fifteen health...

Chemosensory systems (CSS) are complex regulatory pathways capable of perceiving external signals and translating them into different cellular behaviors such as motility and development. In the δ-proteobacterium Myxococcus xanthus, chemosensing allows groups of cells to orient themselves and aggregate into specialized multicellular biofilms termed fruiting bodies. M. xanthus contains eight pred...

This article reviews the basic properties of breath-holding in humans and the possible causes of the breath at breakpoint. The simplest objective measure of breath-holding is its duration, but even this is highly variable. Breath-holding is a voluntary act, but normal subjects appear unable to breath-hold to unconsciousness. A powerful involuntary mechanism normally overrides voluntary breath-h...

Eusocial insects, mostly Hymenoptera, have evolved unique colonial lifestyles that rely on the perception of social context mainly through pheromones, and chemoreceptors are hypothesized to have played important adaptive roles in the evolution of sociality. However, because chemoreceptor repertoires have been characterized in few social insects and their solitary relatives, a comprehensive exam...