Effects of Gadolinium on Calcium-Sensing Receptor (CaR)-mediated Calcium Current in Rat Superior Cervical Ganglia

Abstract

Gadolinium, a Calcium-sensing Receptor (CaR) agonist, was applied in different concentrations to rat Superior Cervical Ganglia (SCG) to discover the dissociation constant and the maximum amount of CaR-mediated current that could be blocked by this agonist. It was hypothesized that these concentrations would be similar to those of previously determined concentrations for other neural tissues, suggesting a similar CaR complex shared by the tissues. The SCG were dissected from male rats, cultured, and neural activity was recorded through a modified patch-clamping technique. It was shown that gadolinium’s dissociation constant was in the hundreds of nanomolars (nM), and that the agonist could block all CaR-mediated current. Previous research has shown gadolinium blocking other important calcium channels, however, and ultimately a method of blocking only the current generated by the CaR is desired to gain control of excess neurological activity as seen in stroke, cerebral ischemia, and seizures.