Please use this identifier to cite or link to this item: https://scholarbank.nus.edu.sg/handle/10635/101970
Title: The mudskipper, Periophthalmodon schlosseri, actively transports NH4/+ against a concentration gradient
Authors: Randall, D.J.
Wilson, J.M.
Peng, K.W.
Kok, T.W.K.
Kuah, S.S.L.
Chew, S.F.
Lam, T.J. 
Ip, Y.K. 
Keywords: Amiloride
Ammonia
Na+-NH4/+-ATPase
Ouabain
Issue Date: Dec-1999
Citation: Randall, D.J.,Wilson, J.M.,Peng, K.W.,Kok, T.W.K.,Kuah, S.S.L.,Chew, S.F.,Lam, T.J.,Ip, Y.K. (1999-12). The mudskipper, Periophthalmodon schlosseri, actively transports NH4/+ against a concentration gradient. American Journal of Physiology - Regulatory Integrative and Comparative Physiology 277 (6 46-6) : R1562-R1567. ScholarBank@NUS Repository.
Abstract: Periophthalmodon schlosseri can maintain ammonia excretion rates and low levels of ammonia in its tissues when exposed to 8 and 30 mM NH4Cl, but tissue ammonia levels rise when the fish is exposed to 100 mM NH4Cl in 50% seawater. Because the transepithelial potential is not high enough to maintain the NH4/+ concentration gradient between blood and water, ammonia excretion under such a condition would appear to be active. Branchial Na+- K+ATPase activity is very high and can be activated by physiological levels of NH4 + instead of K+. Ammonia excretion by the fish against a concentration gradient is inhibited by the addition of ouabain and amiloride to the external medium. It is concluded that Na+-K+-ATPase and an Na+/H+ exchanger may be involved in the active excretion of ammonia across the gills. This unique ability of P. schlosseri to actively excrete ammonia is related to the special structure of its gills and allows the fish to continue to excrete ammonia while air exposed or in its burrow.
Source Title: American Journal of Physiology - Regulatory Integrative and Comparative Physiology
URI: http://scholarbank.nus.edu.sg/handle/10635/101970
ISSN: 03636119
Appears in Collections:Staff Publications

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