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Comparison of pulmonary vascular response to endogenous nitric oxide inhibition in sheep and pigs living at 2,300 m.
J Comp Physiol B. 2004 Oct; 174(7):549-54.JC

Abstract

To compare the role of nitric oxide in an adaptive process to chronic hypoxia, we examined the effects of endogenous nitric oxide synthase inhibition on pulmonary vascular tone in conscious sheep and pigs living at high altitude. Unanesthetized male sheep (n = 6) and pigs (n = 5), born and residing in the highlands of Qinghai Province, China (2,300-3,000 m a.s.l.) were studied at that altitude. Pulmonary artery pressure (P(pa)), pulmonary artery wedge pressure (P(cwp)), and cardiac output (CO) were measured. Pulmonary vascular resistance (PVR) was calculated as (P(pa)- P(cwp))/ CO. Using a climatic chamber, hemodynamic measurements during exposures to atmospheric pressures corresponding to altitudes of 0, 2,300, and 4,500 m a.s.l. were performed with and without NO inhibition, using N(w)-nitro- L-argine (NLA; 20 mg kg(-1)), a potent stereospecific competitive inhibitor of nitric oxide synthase. P(pa) and PVR at baseline (2,300 m) and during hypoxic exposure (4,500 m) were significantly higher in pigs than in sheep. After NLA administration, P(pa) increased and CO decreased in both animals, resulting in significantly increased PVR at baseline and during hypoxic exposure. However, there were no significant differences in the percent increase in basal or hypoxic PVR after NLA administration between sheep and pigs. We conclude that augmented endogenous NO production could contribute to the regulation of pulmonary vascular tone at high altitude in sheep and pigs. However, it is unlikely that NO is responsible for the different pulmonary vascular tones between sheep and pigs at basal condition at moderately high altitude.

Authors+Show Affiliations

First Department of Medicine, Shinshu University School of Medicine, 3-1-1 Asahi, 390-8621, Nagano, Matsumoto, Japan.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15309479

Citation

Ruan, Zonghai, et al. "Comparison of Pulmonary Vascular Response to Endogenous Nitric Oxide Inhibition in Sheep and Pigs Living at 2,300 M." Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology, vol. 174, no. 7, 2004, pp. 549-54.
Ruan Z, Koizumi T, Sakai A, et al. Comparison of pulmonary vascular response to endogenous nitric oxide inhibition in sheep and pigs living at 2,300 m. J Comp Physiol B. 2004;174(7):549-54.
Ruan, Z., Koizumi, T., Sakai, A., Ishizaki, T., Wang, Z., Chen, Q., & Wang, X. (2004). Comparison of pulmonary vascular response to endogenous nitric oxide inhibition in sheep and pigs living at 2,300 m. Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology, 174(7), 549-54.
Ruan Z, et al. Comparison of Pulmonary Vascular Response to Endogenous Nitric Oxide Inhibition in Sheep and Pigs Living at 2,300 M. J Comp Physiol B. 2004;174(7):549-54. PubMed PMID: 15309479.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Comparison of pulmonary vascular response to endogenous nitric oxide inhibition in sheep and pigs living at 2,300 m. AU - Ruan,Zonghai, AU - Koizumi,Tomonobu, AU - Sakai,Akio, AU - Ishizaki,Takeshi, AU - Wang,Zhangang, AU - Chen,Qiuhong, AU - Wang,Xiaoqin, Y1 - 2004/08/11/ PY - 2004/07/16/accepted PY - 2004/8/17/pubmed PY - 2005/3/4/medline PY - 2004/8/17/entrez SP - 549 EP - 54 JF - Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology JO - J Comp Physiol B VL - 174 IS - 7 N2 - To compare the role of nitric oxide in an adaptive process to chronic hypoxia, we examined the effects of endogenous nitric oxide synthase inhibition on pulmonary vascular tone in conscious sheep and pigs living at high altitude. Unanesthetized male sheep (n = 6) and pigs (n = 5), born and residing in the highlands of Qinghai Province, China (2,300-3,000 m a.s.l.) were studied at that altitude. Pulmonary artery pressure (P(pa)), pulmonary artery wedge pressure (P(cwp)), and cardiac output (CO) were measured. Pulmonary vascular resistance (PVR) was calculated as (P(pa)- P(cwp))/ CO. Using a climatic chamber, hemodynamic measurements during exposures to atmospheric pressures corresponding to altitudes of 0, 2,300, and 4,500 m a.s.l. were performed with and without NO inhibition, using N(w)-nitro- L-argine (NLA; 20 mg kg(-1)), a potent stereospecific competitive inhibitor of nitric oxide synthase. P(pa) and PVR at baseline (2,300 m) and during hypoxic exposure (4,500 m) were significantly higher in pigs than in sheep. After NLA administration, P(pa) increased and CO decreased in both animals, resulting in significantly increased PVR at baseline and during hypoxic exposure. However, there were no significant differences in the percent increase in basal or hypoxic PVR after NLA administration between sheep and pigs. We conclude that augmented endogenous NO production could contribute to the regulation of pulmonary vascular tone at high altitude in sheep and pigs. However, it is unlikely that NO is responsible for the different pulmonary vascular tones between sheep and pigs at basal condition at moderately high altitude. SN - 0174-1578 UR - https://www.unboundmedicine.com/medline/citation/15309479/Comparison_of_pulmonary_vascular_response_to_endogenous_nitric_oxide_inhibition_in_sheep_and_pigs_living_at_2300_m_ L2 - http://dx.doi.org/10.1007/s00360-004-0443-3 DB - PRIME DP - Unbound Medicine ER -