Natriuretic Peptides in Antarctic Teleosts and Cardiac Receptors
4~------------------------~=---' fJ site 1
500
Q: 400
. .
E
:;; 300
S
~
= E
J: A
~ 200
= 8
J: C. hamatus
121 site 2
26
381
B
~ : i { : . :
: : . : : ' : . : ~ : : : ' : . : " : . : ' . ' . : " ' . : : : . : ' . '
. .
: : . ' : . : ' : . : " : . : : . : . : :
~ ~ · : r : ; :
O~·A~tr~iu-m~~~~~L-~~~~~~~
myocardium endocardiwn inner layer
outer layer
Cardiac regions
209
Fig. 2. Bar representation of Kd and Bmax values (indicated on each bar) ± SEM
obtained from the Scatchard analysys of saturation curves of[125I]-rANP in the cardiac
regions of C. hamatus and T bernacchii (n=3)
The atrium, the ventricular myocardium and endocardium contained
rANP receptors with very similar Kd values for both the high and the
low affinities (6.7±1.2/S.9±3 pM and 214±511262±90 pM, respectively).
Also the maximal binding capacity was found to be in the same range
(11S±361159±29 fmol/mg p). In the case of the inner and outer layers of
the bulbus arteriosus, site 2 exhibited slightly lower Kd values (156±61