Nishiye H, Mashima H, Ishida A
Jpn J Physiol. 1980;30(1):131-6. doi: 10.2170/jjphysiol.30.131.
Nexus membranes were isolated from cardiac muscles of guinea pig or ox. It was confirmed by autoradiography that Ca2+ was actually bound with the nexus, and by atomic absorption spectroscopy that bound Ca increased extensively at [Ca2+] higher than 10(-6) to 10(-5) M and showed the dose-response relationship against [Ca2+].