Intracerebroventricular serotonin reduces the degree of acute hypoxic ventilatory depression in peripherally chemodenervated rabbits.

Hypoxia causes changes in the rate of synthesis or release of neurotransmitters in the brain. The accumulation of serotonin (5-HT) in the central nervous system might cause hypoxic respiratory depression. In the present study, we aimed to examine the role of central 5-HT on normoxic and acute hypoxic ventilatory depression (AHVD) in peripheral chemoreceptors denervated rabbits.

The reflex effects on the respiratory regulation of the CO2 at the different flow rate and concentration.

Purpose: The purpose of this study was to investigate the activation of the respiratory centers during insufflation of the larynx with CO2 at different flow rates and concentrations.

Materials And Methods: The experiments were carried out in spontaneous air breathing rabbits, anesthetized with thiopental sodium (25 mg kg(-1) i.v.

Respiratory alterations due to chronic long-term intermittent hypobaric hypoxia in rabbits: importance of peripheral chemoreceptors.

Background: None of the studies carried out so far investigated the effect of denervation of peripheral chemoreceptors on basal ventilation and respiratory responses to acute hypoxia in subjects exposed to chronic long-term intermittent hypobaric hypoxia (CLTIHH). We aimed to research (i) the effect of CLTIHH (430 mmHg, 5 h/day, 5 days/week, 5 weeks) on basal ventilation and respiratory responses to hypoxia and (ii) the effects of CLTIHH on central respiratory mechanisms after peripheral chemodenervation.

Methods: Sixteen adult albino rabbits were divided into two groups: CLTIHH (n = 8) and control (n = 8).

The role of peripheral chemoreceptor activity on the respiratory responses to hypoxia and hypercapnia in anaesthetised rabbits with induced hypothyroidism.

The purpose of this study was to investigate the role of peripheral chemoreceptor activity on the hypoxic and hypercapnic ventilatory drives in rabbits with induced hypothyroidism. Experiments were carried out in control and hypothyroid rabbits. Hypothyroidism was induced by an administration of an iodide-blocker, methimazole in food (75 mg/100 g food) for ten weeks.

The effects of vagal stimulation on laryngeal vascular resistance and intraluminal pressure in the dog.

In anaesthetized dogs (sodium pentobarbitone 30 mg/kg, i.v.) laryngeal vascular resistance was measured by unilateral perfusion at constant flow of the branch of the cranial superior thyroid artery that supplies the larynx.

Hypoxic initiation of pulmonary hypertension is mediated by serotonin secretion from neuroepithelial bodies in chemodenervated dogs.

The purpose of this study was to investigate the stimulatory effect of hypoxia on the secretion of serotonin by neuroepithelial bodies (NEB) as well as to determine the relation between its level and changes in pulmonary arterial pressure (PAP) and also to determinate the effect of serotonin antagonists (pizotifen and methysergide) on the responses of pulmonary and systemic arterial pressures. The experiments were carried out in peripheral chemoreceptor-denervated dogs anesthetized with Na penthabarbital (30 mg/kg i.v.

The effect of intracerebroventricular dopamine administration on the respiratory response to hypoxia.

Acute hypoxia produces an increase in ventilation. When the hypoxia is sustained, the initial increase in ventilation is followed a decrease in ventilation. The precise mechanism of this decline in ventilation during sustained hypoxia is unknown.