A calcium channel reversibly blocked by omega-conotoxin GVIA lacking the class D alpha 1 subunit.

In acutely dissociated rat medium-spiny neostriatal neurons, a substantial fraction (approximately 40%) of the calcium current block by omega-conotoxin-GVIA (CgTx) reverses rapidly with washing. The reversibly blocked current differed in voltage dependence from the current irreversibly blocked by CgTx. To test the hypothesis that the reversibly blocked current was attributable to calcium channels with a class D alpha 1 subunit, acutely isolated neurons were subjected to combined patch clamp/reverse transcription-polymerase chain reaction analysis. These studies revealed no correlation between the reversibility of the CgTx block and the expression of class D alpha 1 subunit mRNA.