CACNA1C and Constipation: Moreover, the transcription of CACNA1C in the Urd-treated C3 KO model was higher than in the Lop-induced constipation model, while, after treatment with AELP, the transcription of CACNA1C was greater in the Lop-induced constipation model than in the C3 KO model (Figure 8G and Table 8).