Voltage-gated sodium channel is the target site of many insecticidal compounds including pyrethroid insecticide. We studied molecular variants of an alpha subunit of sodium channel of tobacco budworm, Heliothis virescens, a major cotton pest.  We have investigated alternatively spliced regions of the hscp (Heliothis virescens F.  Sodium Channel Para-homologous gene) which were previously discussed (Park et al., Ins. Mol. Bio. 1999, 8:161). We found additional splicing variants in the putative cytoplasmic linker between homology domain I and domain II. Total five different splicing variants were found in this region with complex usages of the exons (exons 11a to 11e). Only two of the five variants encoded complete in-frame channel transcripts and other three variants contained premature stop codons generated by frame-shifts in the alternative use of exons.  Thereby, the premature terminations of open reading frame result in the putative channel structure with only one homology domain that is contrasted to the full length structure composed of four homology domains. Further investigation for understanding biological functions of the alternatively spliced variants of the hscp is in progress.