Pkc-a differentially affects rutabaga and wild-type Drosophila neuronal potassium current.

Learning and memory are defective in the Drosophila mutant rutabaga, which has a low intracellular cyclic adenosine monophosphate (cAMP) concentration. The aim of this study was to compare modulation effects of protein kinase C activator (PKC-A) on the delayed-rectifier potassium current (IKDR) in wild-type and rutabaga neurons. IKDR was measured from cultured (2 days) wild-type and rutabaga neurons. The authors examined the effects of PKC-A on IKDR in wild-type and rutabaga neurons. IKDR was measured from neurons before and after addition of PKC-A to the external solution. IKDR was smaller in rutabaga neurons (380 +/- 25 pA) than in wild-type neurons (529 +/- 44 pA). IKDR was reduced by PKC-A more in wild-type (decreasing 55 +/- 6%) than in rutabaga (decreasing 35 +/- 8%) neurons (single-cell studies). In the presence of PKC-A, there was no difference in IKDR between wild-type (229 +/- 31 pA) and rutabaga (242 +/- 26 pA) neurons (population studies). These results indicate that PKC-A differentially affects the delayed-rectifier channel in wild-type rutabaga.