Sensitivity of ventilation and brain metabolism to ammonia exposure in rainbow trout, Oncorhynchus mykiss

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	Sensitivity of ventilation and brain metabolism to ammonia exposure in rainbow trout, Oncorhynchus mykiss
	[Zhang, Li ; Nawata, C. Michele ; Wood, Chris M.] McMaster Univ, Dept Biol, Hamilton, ON L8S 4K1, Canada ; [Zhang, Li] Chinese Acad Sci, South China Sea Inst Oceanol, Key Lab Marine Bioresources Sustainable Utilizat, Guangzhou 510301, Guangdong, Peoples R China ; [Nawata, C. Michele] Univ Arizona, Dept Physiol, Tucson, AZ 85724 USA
刊名	JOURNAL OF EXPERIMENTAL BIOLOGY
	2013
卷号	216 期号:21 页码:4025-4037
关键词	Rh protein ammonia brain fish glutamine synthetase ventilation
ISSN号	0022-0949
通讯作者	zhangli@scsio.ac.cn
中文摘要	Ammonia has been documented as a respiratory gas that stimulates ventilation, and is sensed by peripheral neuroepithelial cells (NECs) in the gills in ammoniotelic rainbow trout. However, the hyperventilatory response is abolished in trout chronically exposed (1+ months) to high environmental ammonia [HEA; 250 mu mol l(-1) (NH4)(2)SO4]. This study investigates whether the brain is involved in the acute sensitivity of ventilation to ammonia, and whether changes in brain metabolism are related to the loss of hyperventilatory responses in trout chronically exposed to HEA ('HEA trout'). Hyperventilation (via increased ventilatory amplitude rather than rate) and increased total ammonia concentration ([T-Amm]) in brain tissue were induced in parallel by acute HEA exposure in control trout in a concentration-series experiment [500, 750 and 1000 mu mol l(-1) (NH4)(2)SO4], but these inductions were abolished in HEA trout. Ventilation was correlated more closely to [T-Amm] in brain rather than to [T-Amm] in plasma or cerebrospinal fluid. The close correlation of hyperventilation and increased brain [T-Amm] also occurred in control trout acutely exposed to HEA in a time-series analysis [500 mu mol l(-1) (NH4)(2)SO4; 15, 30, 45 and 60 min], as well as in a methionine sulfoxamine (MSOX) pre-injection experiment [to inhibit glutamine synthetase (GSase)]. These correlations consistently suggest that brain [T-Amm] is involved in the hyperventilatory responses to ammonia in trout. The MSOX treatments, together with measurements of GSase activity, T-Amm, glutamine and glutamate concentrations in brain tissue, were conducted in both the control and HEA trout. These experiments revealed that GSase plays an important role in transferring ammonia to glutamate to make glutamine in trout brain, thereby attenuating the elevation of brain [T-Amm] following HEA exposure, and that glutamate concentration is reduced in HEA trout. The mRNAs for the ammonia channel proteins Rhbg, Rhcg1 and Rhcg2 were expressed in trout brain, and the expression of Rhbg and Rhcg2 increased in HEA trout, potentially as a mechanism to facilitate the efflux of ammonia. In summary, the brain appears to be involved in the sensitivity of ventilation to ammonia, and brain ammonia levels are regulated metabolically in trout.
学科主题	Biology
资助信息	This work was supported by a Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant and a Canada Foundation for Innovation (CFI) award to C. M. W., who is also supported by the Canada Research Chairs Program.
原文出处	COMPANY OF BIOLOGISTS LTD
语种	英语
WOS记录号	WOS:000325806300018
公开日期	2015-01-22
内容类型	期刊论文
源URL	[http://ir.scsio.ac.cn/handle/344004/10975]
专题	南海海洋研究所_中科院海洋生物资源可持续利用重点实验室
推荐引用方式 GB/T 7714	[Zhang, Li,Nawata, C. Michele,Wood, Chris M.] McMaster Univ, Dept Biol, Hamilton, ON L8S 4K1, Canada,et al. Sensitivity of ventilation and brain metabolism to ammonia exposure in rainbow trout, Oncorhynchus mykiss[J]. JOURNAL OF EXPERIMENTAL BIOLOGY,2013,216(21):4025-4037.
APA	[Zhang, Li,Nawata, C. Michele,Wood, Chris M.] McMaster Univ, Dept Biol, Hamilton, ON L8S 4K1, Canada,[Zhang, Li] Chinese Acad Sci, South China Sea Inst Oceanol, Key Lab Marine Bioresources Sustainable Utilizat, Guangzhou 510301, Guangdong, Peoples R China,&[Nawata, C. Michele] Univ Arizona, Dept Physiol, Tucson, AZ 85724 USA.(2013).Sensitivity of ventilation and brain metabolism to ammonia exposure in rainbow trout, Oncorhynchus mykiss.JOURNAL OF EXPERIMENTAL BIOLOGY,216(21),4025-4037.
MLA	[Zhang, Li,et al."Sensitivity of ventilation and brain metabolism to ammonia exposure in rainbow trout, Oncorhynchus mykiss".JOURNAL OF EXPERIMENTAL BIOLOGY 216.21(2013):4025-4037.