Branchial cobalt uptake in the carp, Cyprinus carpio: Effect of calcium channelblockers and calcium injection

• Published in: Fish physiology and biochemistry 1998-02, Vol.18 (1), p.1
• Main Authors: Comhaire, S, Blust, R, Van Ginneken, L, Verbost, Pm, Vanderborght, Olj
• Format: Article
• Language: English
• Subjects: Calcium channels; Calcium chloride; Cobalt; Injection
• ISSN: 0920-1742; 1573-5168
• DOI: 10.1023/A:1007746117932

Using tracer-uptake studies we investigated whether the branchial uptakeof cobalt occurs via selective, inhibitable, calcium uptake routes.Modulation of the calcium transport system was performed using generalcalcium channel blockers (Cd^sup 2+^, La^sup 3+^,Mg^sup 2+^), a voltage-dependent calcium channel blocker (diltiazem)and an intraperitoneal CaCl2 injection. Adding Cd^sup 2+^ orMg^sup 2+^ to thewater or injecting the fish with theCa^sup 2+^-solution resulted in decreased Co^sup 2+^ andCa^sup 2+^ uptake rates. Addition of La^sup 3+^ reducedCa^sup 2+^ and Co^sup 2+^ uptake rates except forCo^sup 2+^ uptake in the gills. Diltiazem displayed only aninconsistent, concentration-independent blocking of the uptake of bothCo^sup 2+^ and Ca^sup 2+^. All inhibitors which inhibitCa^sup 2+^ uptake also inhibit Co^sup 2+^ uptake. However, aclear difference in the degree of inhibition of uptake of both elements isobserved. Two possible explanations are suggested (1) Co^sup 2+^ andCa^sup 2+^ are both transported through the gills via the sametransport system or (2) the calcium transport system is not the only systeminvolved in the transport of Co^sup 2+^.[PUBLICATION ABSTRACT]