Short-Term Sustained Hypoxia Elevates Basal and Hypoxia-Induced Ventilation but Not the Carotid Body Chemoreceptor Activity in Rats
| Autor: | Karine C. Flor, Elaine Fernanda Silva, Gustavo Rodrigues Pedrino, Eduardo Colombari, Daniel B. Zoccal, Miguel Furtado Menezes |
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| Přispěvatelé: | Universidade Estadual Paulista (Unesp), Universidade Federal de Goiás (UFG) |
| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
medicine.medical_specialty Chemoreceptor Physiology chemoreceptor Hypoxic ventilatory response lcsh:Physiology ventilatory acclimatization 03 medical and health sciences 0302 clinical medicine Physiology (medical) Internal medicine medicine Normocapnia Respiratory system Tidal volume Original Research active expiration lcsh:QP1-981 business.industry hypoxic ventilatory response Hypoxia (medical) sympathetic activity carotid body 3. Good health 030104 developmental biology medicine.anatomical_structure Endocrinology Carotid body medicine.symptom business 030217 neurology & neurosurgery Respiratory minute volume |
| Zdroj: | Web of Science Repositório Institucional da UNESP Universidade Estadual Paulista (UNESP) instacron:UNESP Frontiers in Physiology, Vol 9 (2018) Frontiers in Physiology |
| ISSN: | 1664-042X |
| DOI: | 10.3389/fphys.2018.00134 |
| Popis: | Made available in DSpace on 2018-11-26T17:48:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-02-27 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) NIH Exposure to chronic sustained hypoxia (SH), as experienced in high altitudes, elicits an increase in ventilation, named ventilatory acclimatization to hypoxia (VAH). We previously showed that rats exposed to short-term(24 h) SH exhibit enhanced abdominal expiratory motor activity at rest, accompanied by augmented baseline sympathetic vasoconstrictor activity. In the present study, we investigated whether the respiratory and sympathetic changes elicited by short-term SH are accompanied by carotid body chemoreceptor sensitization. Juvenile male Holtzman rats (60-80 g) were exposed to SH (10% O-2 for 24 h) or normoxia (control) to examine basal and hypoxic-induced ventilatory parameters in unanesthetized conditions, as well as the sensory response of carotid body chemoreceptors in artificially perfused in situ preparations. Under resting conditions (normoxia/normocapnia), SH rats (n = 12) exhibited higher baseline respiratory frequency, tidal volume, and minute ventilation compared to controls (n = 11, P < 0.05). SH group also showed greater hypoxia ventilatory response than control group (P < 0.05). The in situ preparations of SH rats (n = 8) exhibited augmented baseline expiratory and sympathetic activities under normocapnia, with additional bursts in abdominal and thoracic sympathetic nerves during late expiratory phase that were not seen in controls (n = 8, P < 0.05). Interestingly, basal and potassium cyanide-induced afferent activity of carotid sinus nerve (CSN) was similar between SH and control rats. Our findings indicate that the maintenance of elevated resting ventilation, baseline sympathetic overactivity, and enhanced ventilatory responses to hypoxia in rats exposed to 24 h of SH are not dependent on increased basal and sensorial activity of carotid body chemoreceptors. Sao Paulo State Univ, Dept Physiol & Pathol, Araraquara, Brazil Univ Fed Goias, Dept Physiol Sci, Goiania, Go, Brazil Sao Paulo State Univ, Dept Physiol & Pathol, Araraquara, Brazil FAPESP: 2013/17.251-6 FAPESP: 2015/23.568-8 CNPq: 302892/2014-1 NIH: R01AT008632 |
| Databáze: | OpenAIRE |
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