histamine/hypoxia

1 A procedure involving two guinea-pig isolated hearts perfused in series is described for detecting in the recipient heart the release of a possible coronary vasodilator metabolite from the donor heart. 2 Adrenaline and isoprenaline stimulated the rate and force of contraction and produced a

The effect of vagal reflexes on bronchomotor tone can be altered by their interaction with other bronchomotor factors, such as the prevailing state of oxygenation. In anesthetized, paralyzed, and artificially ventilated dogs, a reflex constriction was induced in an isolated tracheal segment by

Central histamine has crucial roles in circadian rhythm, ventilation, and the balance of energy metabolism via H1 receptors. We focused on the variation in ventilatory responses to hypoxia between light and dark periods, and the requirement of histamine H1 receptors for the circadian variation,

The aim of the present study was to compare the effect of reduced oxygenation on the contractions of pulmonary vascular and airway smooth muscle induced by leukotriene D4 (LTD4) with those induced by histamine (an agonist with similar mechanisms of smooth muscle contraction) and KCl (a

Experimental evidence from animals suggests that the response of the pulmonary circulation to hypoxia is mediated by histamine. In 3 patients with chronic bronchitis the pulmonary vascular response to hypoxia was measured before and after administration of chlorpheniramine, a competitive antagonist

Hypoxia elicited a remarkable decrease in contractility and heart rate in isolated right atria from guinea pigs, a decrease which recovered partially during reoxygenation. Histamine content increased during hypoxia and decreased during reoxygenation. However, hypoxia induced a marked degranulation

We tested the hypothesis that the biphasic ventilatory response to poikilocapnic hypoxia shows circadian variation and contribution of histamine H1 receptors in mice. Initial increases in ventilation were augmented during dark periods. H1 receptors had no major relationship with circadian variation,

The rapid shallow breathing of pulmonary vagal origin following administration of histamine (H) and phenyldiguanide (PDG) was studied at different levels of hypercapnic and hypoxic stimulation. At all levels of chemical drive H and PDG caused an excitatory effect on timing of breathing and an

Histamine level (HA), the activities of the HA synthetizing enzyme--histidine decarboxylase (HD) and HA metabolizing enzyme--histamine methyltransferase (HMT) and the uptake and release of histidine and histamine were analyzed in synaptosomal preparations obtained from rats with brain hypoxia and

During exercise in highly-trained older master athletes (MA), the impairment of pulmonary gas exchanges has been shown to be associated with a concomitant increase in histamine release (2). To determine the role of the histamine released (% H) during exercise-induced hypoxemia, seven MA (age 63.2 yr

We sought to define the roles of H1-and H2-receptors in the cat and to evaluate the roles of these receptors during alveolar hypoxia. In pentobarbital anesthetized cats, we found that histamine infusion (1.1 microgram/kg/min for 3 min) increased cardiac output and decreased pulmonary and systemic

The ability of hypoxia (PO2 57 Torr) and anoxia (PO2 0 Torr) to induce the release of histamine or sulfidopeptide leukotrienes from dispersed porcine parenchymal lung cells was examined. Spontaneous release of histamine (9.2 +/- 1.3%) was not significantly increased during hypoxia or anoxia, and

1. The effects of hypoxia, histamine-receptor agonist perfusion, and their combination on cardiac rhythm were studied in isolated rat hearts. 2. While hypoxia induced a high incidence of ventricular tachycardia or fibrillation, only a few preparations developed ventricular arrhythmias in response to

To determine whether exercise-induced hypoxemia in extreme athletes results from an increase in histamine level during maximal incremental exercise, seven young athletes [YA; age 22.2 +/- 1.23 (SE) yr] and seven master athletes (MA; age 66.2 +/- 2.94 yr), all of whom were known to develop

Using an isolated perfused cat lung preparation we examined the effects of hypoxia and histamine infusion on the lung blood volume. Total lung blood volume was determined from the indocyanine green transit time and the ether bolus technique was used to estimate arterial and venous volumes during