Postnatal development of right atrial injection of capsaicin-induced apneic response in rats

2006 ◽  
Vol 101 (1) ◽  
pp. 60-67 ◽  
Author(s):  
Rurong Wang ◽  
Fadi Xu
Keyword(s):  
Respiratory Failure ◽  
Postnatal Development ◽  
Pulmonary Disease ◽  
Bolus Injection ◽  
Right Atrial ◽  
Newborn Rats ◽  
Respiratory Dysfunction ◽  
Percent Change ◽  
C Fiber ◽  
Spontaneously Breathing

Apnea and respiratory failure often occur in infants with pulmonary disease. Bronchopulmonary C-fiber (PCF)-mediated apnea is an important component of respiratory dysfunction. This study was undertaken to define the postnatal development of PCF-mediated apnea. The experiments were conducted in five groups of anesthetized, tracheotomized, and spontaneously breathing rats with ages at postnatal days P1–3, P7–9, P14–16, P21–23, and P56–58. Right atrial bolus injection of three doses of capsaicin (Cap), equivalent to 2, 4, and 8 μg/kg used previously in 450-g rats, was applied to stimulate PCFs. We found that 1) Cap-induced apneic response [percent change from the baseline expiratory duration (Te) values (ΔTe%)] and the sensitivity of this response (ΔTe%·μg−1) were significantly greater in the rats <P10 than those >P10; 2) the Cap-induced apneas were vagally dependent in all rats tested; and 3) bivagotomy-induced prolongation of Te was much greater in the rats <P10 than those >P10. From these findings we concluded that, compared with the older rats (>P10), the newborn rats have a stronger PCF-mediated respiratory inhibition that may contribute to infants' vulnerability to respiratory failure.

Metoclopramide blocks the phenyl diguanide and 5-hydroxytryptamine induced cardiorespiratory reflexes in cats and dogs

1988 ◽  
Vol 66 (6) ◽  
pp. 776-782 ◽  
Author(s):  
K. Ravi ◽  
N. B. Dev
Keyword(s):  
Left Atrial ◽  
Right Atrial ◽  
Excitatory Effect ◽  
Reflex Responses ◽  
Cardiorespiratory Responses ◽  
C Fiber ◽  
Spontaneously Breathing ◽  
Cardiac Receptors ◽  
Sensory Endings ◽  
Stimulation Of

The effects of metoclopramide on the reflex cardiorespiratory responses elicited by stimulation of pulmonary J receptors by right atrial injections of phenyl diguanide (PDG), 5-hydroxytryptamine (5-HT), and capsaicin were investigated in anesthetized spontaneously breathing cats. It was observed that while metoclopramide blocked the responses to PDG and 5-HT injections, it spared the responses to capsaicin injections. Similarly, metoclopramide was without effect on the reflex responses following activation of pulmonary C-fiber receptors (J receptors) by capsaicin in dogs. Reflex cardiorespiratory responses elicited by left atrial injections of PDG and 5-HT, owing to stimulation of cardiac receptors in cats, and reflex responses following right or left atrial injections of PDG and 5-HT, owing to stimulation of aortic chemoreceptors in dogs, were also found to be blocked by metoclopramide. Afferent impulse activity recorded from aortic chemoreceptors of dogs showed that while metoclopramide depressed the excitatory effect of PDG and 5-HT on them, it did not produce any effect on their spontaneous activity and their excitation by hypoxia. The results from the reflex studies show that metoclopramide is capable of antagonizing the reflex responses following the activation of the cardiopulmonary afferents by PDG and 5-HT. Based on the effects on aortic chemoreceptor afferents, it is suggested that PDG, 5-HT, and metoclopramide may be acting upon the regenerative region of the sensory endings.

scholarly journals 8-OH-DPAT abolishes the pulmonary C-fiber-mediated apneic response to fentanyl largely via acting on 5HT1A receptors in the nucleus tractus solitarius

2012 ◽  
Vol 303 (4) ◽  
pp. R449-R458 ◽  
Author(s):  
Jianguo Zhuang ◽  
Zhenxiong Zhang ◽  
Cancan Zhang ◽  
Fadi Xu
Keyword(s):  
Bolus Injection ◽  
Nucleus Tractus Solitarius ◽  
Right Atrial ◽  
Selective Blockade ◽  
C Fibers ◽  
5Ht1a Receptors ◽  
Way 100635 ◽  
Before And After ◽  
Μ Opioid Receptor ◽  
Spontaneously Breathing

Intravenous bolus injection of morphine causes a vagal-mediated brief apnea (∼3 s), while continuous injection, via action upon central μ-opioid receptor (MOR), arrests ventilation (>20 s) that is eliminated by stimulating central 5-hydroxytryptamine 1A receptors (5HT1ARs). Bronchopulmonary C-fibers (PCFs) are essential for triggering a brief apnea, and their afferents terminate at the caudomedial region of the nucleus tractus solitarius (mNTS) that densely expresses 5HT1ARs. Thus we asked whether the vagal-mediated apneic response to MOR agonists was PCF dependent, and if so, whether this apnea was abolished by systemic administration of 8-hydroxy-2-(di- n-propylamino)tetral (8-OH-DPAT) largely through action upon mNTS 5HT1ARs. Right atrial bolus injection of fentanyl (5.0 μg/kg, a MOR agonist) was performed in the anesthetized and spontaneously breathing rats before and after: 1) selective blockade of PCFs' conduction and subsequent bivagotomy; 2) intravenous administration of 5HT1AR agonist 8-OH-DPAT; 3) intra-mNTS injection of 8-OH-DPAT; and 4) intra-mNTS injection of 5HT1AR antagonist WAY-100635 followed by 8-OH-DPAT (iv). We found the following: First, fentanyl evoked an immediate apnea (2.5 ± 0.4 s, ∼6-fold longer than the baseline expiratory duration, TE), which was abolished by either blocking PCFs' conduction or bivagotomy. Second, this apnea was prevented by systemic 8-OH-DPAT challenge. Third, intra-mNTS injection of 8-OH-DPAT greatly attenuated the apnea by 64%. Finally, intra-mNTS microinjection of WAY-100635 significantly attenuated (58%) the apneic blockade by 8-OH-DPAT (iv). We conclude that the vagal-mediated apneic response to MOR activation depends on PCFs, which is fully antagonized by systemic 8-OH-DPAT challenge largely via acting on mNTS 5HT1ARs.

Acute hypoxia prolongs the apnea induced by right atrial injection of capsaicin

2003 ◽  
Vol 94 (4) ◽  
pp. 1446-1454 ◽  
Author(s):  
Fadi Xu ◽  
Qi-Hai Gu ◽  
Tongrong Zhou ◽  
Lu-Yuan Lee
Keyword(s):  
Bolus Injection ◽  
Acute Hypoxia ◽  
Right Atrial ◽  
Ventilatory Responses ◽  
C Fibers ◽  
Bilateral Vagotomy ◽  
Prolonged Apnea ◽  
The Right ◽  
Spontaneously Breathing ◽  
Stimulation Of

Inspiratory central drive is augmented by acute hypoxia that leads to a hyperventilation, but it is inhibited by capsaicin (Cap)-induced stimulation of pulmonary C fibers (PCFs) that produces an expiratory apnea. We hypothesized that acute hypoxia should shorten or eliminate the Cap-induced apnea. The ventilatory responses to bolus injection of Cap (0.2–0.5 μg) into the right atrium before and during acute hypoxia (10% O2 for ∼1 min; Hypoxia+Cap) were compared in anesthetized and spontaneously breathing rats. We found that Cap injection during acute hypoxia produced an extremely long-lasting apnea (69.67 ± 11.97 s) that was 16-fold longer than the apnea induced by Cap alone (expiratory duration = 4.37 ± 0.53 s; P< 0.01). A similar prolonged apnea was also observed during hypoxia in anesthetized guinea pigs. Bilateral vagotomy abolished apneic responses to Cap both before and during hypoxia. Subsequent recording of single-fiber activity of PCFs (PCFA) showed that acute hypoxia did not significantly affect baseline PCFA but that it doubled PCFA responses to Cap via increasing both the firing rate (3.34 ± 0.76 to 7.65 ± 1.32 impulses/s; P < 0.05) and burst duration (1.12 ± 0.18 to 2.32 ± 0.31 s; P < 0.05). These results suggest that acute hypoxia augments PCF-mediated inspiratory inhibition and thereby leads to an extremely long-lasting apnea. This interaction is partially due to hypoxic sensitization of PCF response to Cap.

scholarly journals Trends in Hospital Admissions for Chronic Obstructive Pulmonary Disease in Men and Women in SPAIN, 1998 to 2018

2021 ◽  
Vol 10 (7) ◽  
pp. 1529
Author(s):  
Domingo Orozco-Beltrán ◽  
Juan Manuel Arriero-Marin ◽  
Concepción Carratalá-Munuera ◽  
Juan J. Soler-Cataluña ◽  
Adriana Lopez-Pineda ◽  
...  
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Pulmonary Disease ◽  
Hospital Admissions ◽  
Chronic Obstructive ◽  
Annual Percent Change ◽  
Data Set ◽  
Obstructive Pulmonary Disease ◽  
Men And Women ◽  
Admission Rates ◽  
Percent Change

The prevalence of chronic obstructive pulmonary disease (COPD) is rising faster in women in some countries. An observational time trends study was performed to assess the evolution of hospital admissions for COPD in men and women in Spain from 1998 to 2018. ICD-9 diagnostic codes (490–492, 496) from the minimum basic data set of hospital discharges were used. Age-standardised admission rates were calculated using the European Standard Population. Joinpoint regression models were fitted to estimate the annual percent change (APC). In 2018, the age-standardised admission rate per 100,000 population/year for COPD was five times higher in men (384.8, 95% CI: 381.7, 387.9) than in women (78.6, 95% CI: 77.4, 79.9). The average annual percent change (AAPC) was negative over the whole study period in men (−1.7%/year, 95% CI: −3.1, −0.2) but positive from 2010 to 2018 (1.1%/year, 95% CI: −0.8, 2.9). In women, the APC was −6.0% (95%CI: −7.1, −4.9) from 1998 to 2010, but the trend reversed direction in the 2010–2018 period (7.8%/year, 95% CI: 5.5, 10.2). Thus, admission rates for COPD decreased from 1998 to 2010 in both men and women but started rising again until 2018, modestly in men and sharply in women.

Effects of dexmedetomidine on cardiorespiratory regulation in spontaneously breathing newborn rats

2014 ◽  
Vol 24 (12) ◽  
pp. 1245-1251 ◽  
Author(s):  
Junko Tamiya ◽  
Ryoji Ide ◽  
Masayuki Takahashi ◽  
Chikako Saiki
Keyword(s):  
Newborn Rats ◽  
Spontaneously Breathing
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