
Fig. 3. Cytosolic calcium [Ca2+]i response of rectal gland
artery (RGA) to external Ca2+ and Gd3+ or to spermine.
(A) Change in [Ca2+]i of RGA maintained in calcium-free
shark Ringer following the addition of Ca2+ (approx. 3 mmol
l-1) and then Gd3+ (333 µmol l-1) (values
are means ± S.E.M., N=10; *P<0.01 for
addition of Ca2+ compared to baseline [Ca2+]i
and **P<0.05 for Gd3+ compared to
Ca2+). (B) Representative example of the increase in
[Ca2+]i of RGA in calcium-free buffer in response to the
addition of spermine (333 µmol l-1) at the time indicated by the
arrow.